Change the Destroy blanket impls to be more specific (#6098)

The main direction of this change is the edits to `destroy.carbon`
(matching in both prelude and min_prelude).

Previously there was a no-op blanket impl for `Destroy`, which hid all
missing implementations of `Destroy`. This does a few things:

- Sets up builtin aggregate destruction for struct and tuple types as
before, but also adds C++ class types and array types to the same
handling. (all as a TODO for actual implementation)
- Also maybe-unformed destruction, for now at least. (there's a chance I
may try a different approach on this, but the impl lookup wasn't working
as I'd hope in order to write it in code)
- Adds handlers for simple things that are easy to do in code: `type`,
`bool`, pointers. (because these are no-op destruction)
- Redirect `const T` destruction to `T` destruction.

This leaves as future issues:

- `partial T` destruction. (this can't be done similar to `const`
because it only works for non-`final` class types; I think `class`
definitions should just generate what's needed)
- Destruction of other prelude-provided types. (will probably come up as
we implement class destruction, that the adapted builtin type doesn't
implement `Destroy` -- but may end up special-casing that in a way that
moots it)

This moves the `&` operator from `facet_types.carbon` to
`convert.carbon` because more things need to handle type and now that
we're getting separate copy and destroy interfaces. It should be
low-cost (an interface and builtin) so hopefully this is the right
balance for complexity and re-use.

A few tests are also edited in order to focus them more on what they
intend to test, and avoid a `Destroy` dependency.

toolchain/lower/testdata/array/base.carbon

@@ -21,10 +21,10 @@ fn Run() {
 // CHECK:STDOUT: ; ModuleID = 'base.carbon'
 // CHECK:STDOUT: source_filename = "base.carbon"
 // CHECK:STDOUT:
-// CHECK:STDOUT: @array.237.loc14_3 = internal constant [1 x i32] [i32 1]
-// CHECK:STDOUT: @array.b91.loc15_3 = internal constant [2 x double] [double 1.110000e+01, double 2.200000e+00]
-// CHECK:STDOUT: @array.1cb.loc16_3 = internal constant [5 x {}] zeroinitializer
-// CHECK:STDOUT: @tuple.loc17_3 = internal constant { i32, i32, i32 } { i32 1, i32 2, i32 3 }
+// CHECK:STDOUT: @array.237.loc14_3.1 = internal constant [1 x i32] [i32 1]
+// CHECK:STDOUT: @array.b91.loc15_3.1 = internal constant [2 x double] [double 1.110000e+01, double 2.200000e+00]
+// CHECK:STDOUT: @array.1cb.loc16_3.1 = internal constant [5 x {}] zeroinitializer
+// CHECK:STDOUT: @tuple.loc17_3.1 = internal constant { i32, i32, i32 } { i32 1, i32 2, i32 3 }
 // CHECK:STDOUT:
 // CHECK:STDOUT: define void @main() !dbg !4 {
 // CHECK:STDOUT: entry:
@@ -35,23 +35,23 @@ fn Run() {
 // CHECK:STDOUT:   %e.var = alloca [3 x i32], align 4, !dbg !11
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %a.var), !dbg !7
 // CHECK:STDOUT:   %.loc14_29.3.array.index = getelementptr inbounds [1 x i32], ptr %a.var, i32 0, i64 0, !dbg !12
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %a.var, ptr align 4 @array.237.loc14_3, i64 4, i1 false), !dbg !7
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %a.var, ptr align 4 @array.237.loc14_3.1, i64 4, i1 false), !dbg !7
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %b.var), !dbg !8
 // CHECK:STDOUT:   %.loc15_37.3.array.index = getelementptr inbounds [2 x double], ptr %b.var, i32 0, i64 0, !dbg !13
 // CHECK:STDOUT:   %.loc15_37.6.array.index = getelementptr inbounds [2 x double], ptr %b.var, i32 0, i64 1, !dbg !13
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 8 %b.var, ptr align 8 @array.b91.loc15_3, i64 16, i1 false), !dbg !8
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 8 %b.var, ptr align 8 @array.b91.loc15_3.1, i64 16, i1 false), !dbg !8
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !9
 // CHECK:STDOUT:   %.loc16_45.2.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 0, !dbg !14
 // CHECK:STDOUT:   %.loc16_45.4.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 1, !dbg !14
 // CHECK:STDOUT:   %.loc16_45.6.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 2, !dbg !14
 // CHECK:STDOUT:   %.loc16_45.8.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 3, !dbg !14
 // CHECK:STDOUT:   %.loc16_45.10.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 4, !dbg !14
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %c.var, ptr align 1 @array.1cb.loc16_3, i64 0, i1 false), !dbg !9
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 1 %c.var, ptr align 1 @array.1cb.loc16_3.1, i64 0, i1 false), !dbg !9
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %d.var), !dbg !10
 // CHECK:STDOUT:   %tuple.elem0.loc17.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 0, !dbg !15
 // CHECK:STDOUT:   %tuple.elem1.loc17.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 1, !dbg !15
 // CHECK:STDOUT:   %tuple.elem2.loc17.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 2, !dbg !15
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %d.var, ptr align 4 @tuple.loc17_3, i64 12, i1 false), !dbg !10
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %d.var, ptr align 4 @tuple.loc17_3.1, i64 12, i1 false), !dbg !10
 // CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %e.var), !dbg !11
 // CHECK:STDOUT:   %tuple.elem0.loc18.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 0, !dbg !16
 // CHECK:STDOUT:   %.loc18_26.1 = load i32, ptr %tuple.elem0.loc18.tuple.elem, align 4, !dbg !16