Add builtin functions for destroy, with special requirements in facet types (#6035)

This is in support of a goal of changing the blanket `destroy` impl to
use (roughly):

```
private fn CanAggregateDestroy() -> type = "type.can_aggregate_destroy";

// Handles aggregate type destruction.
impl forall [AggregateDestroyT:! CanAggregateDestroy()] AggregateDestroyT as Destroy {
  fn Op[addr self: Self*]() = "type.aggregate_destroy";
}
```

That isn't done here because there's still other issues that migrating
raises. What this *does* do is add the builtin functions, and in
particular, support to `FacetTypeInfo` to make `CanAggregateDestroy`
work.

The "special requirement" approach in `FacetTypeInfo` allows us to
support restricting a blanket impl under the current approach of impls.
Maybe we'll find a cleaner approach that can work in the future, but
this fits into the current model by propagating similar to other
requirements. I'm using an enum mask because we have a number of similar
things to add (e.g. copy, move) but I'm not sure we need a full vector.

A few alternatives considered were:

- Supporting syntax more like `where .Self impls
TypeCanAggregateDestroy(.Self, SupportedInterface,
UnsupportedInterface)`. I think it'd be a little cleaner, but requires
better compile-time evaluation in order to assess the type of the call.
Right now it's expected to be a `FacetType` too early to make this work,
and I was concerned about pouring too much more time down this route.
- Providing an actual interface, in particular doing name lookup back
into `Core.` for an interface. This would've added name lookup overhead,
and the question of whether an `impl` exists.
- Generating an interface. This avoids the name lookup, but would still
raise the question of whether an `impl` should also be generated. Work
I've previously done generating interfaces for class destruction also
feels complex to both write and understand (an unfortunate issue).
- Still modeling as an `ImplsConstraint`, for example by defining a
special `InterfaceId::CanAggregateDestroy = -2` similar to what we do on
other ids. I was hesitant because of how this expands the number of
modes of `InterfaceId`, and things for consuming code to watch out for,
for what feels like a relatively niche set of use-cases that are only
interface-like.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>

toolchain/check/testdata/interface/basic.carbon

@@ -25,9 +25,9 @@ interface ForwardDeclared {
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
 // CHECK:STDOUT:   %Empty.type: type = facet_type <@Empty> [concrete]
-// CHECK:STDOUT:   %Self.b05: %Empty.type = bind_symbolic_name Self, 0 [symbolic]
+// CHECK:STDOUT:   %Self.e3a: %Empty.type = bind_symbolic_name Self, 0 [symbolic]
 // CHECK:STDOUT:   %ForwardDeclared.type: type = facet_type <@ForwardDeclared> [concrete]
-// CHECK:STDOUT:   %Self.9cc: %ForwardDeclared.type = bind_symbolic_name Self, 0 [symbolic]
+// CHECK:STDOUT:   %Self.dd5: %ForwardDeclared.type = bind_symbolic_name Self, 0 [symbolic]
 // CHECK:STDOUT:   %ForwardDeclared.F.type: type = fn_type @ForwardDeclared.F [concrete]
 // CHECK:STDOUT:   %ForwardDeclared.F: %ForwardDeclared.F.type = struct_value () [concrete]
 // CHECK:STDOUT:   %ForwardDeclared.assoc_type: type = assoc_entity_type @ForwardDeclared [concrete]
@@ -45,7 +45,7 @@ interface ForwardDeclared {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: interface @Empty {
-// CHECK:STDOUT:   %Self: %Empty.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self.b05]
+// CHECK:STDOUT:   %Self: %Empty.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self.e3a]
 // CHECK:STDOUT:
 // CHECK:STDOUT: !members:
 // CHECK:STDOUT:   .Self = %Self
@@ -53,7 +53,7 @@ interface ForwardDeclared {
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: interface @ForwardDeclared {
-// CHECK:STDOUT:   %Self: %ForwardDeclared.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self.9cc]
+// CHECK:STDOUT:   %Self: %ForwardDeclared.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self.dd5]
 // CHECK:STDOUT:   %ForwardDeclared.F.decl: %ForwardDeclared.F.type = fn_decl @ForwardDeclared.F [concrete = constants.%ForwardDeclared.F] {} {}
 // CHECK:STDOUT:   %assoc0: %ForwardDeclared.assoc_type = assoc_entity element0, %ForwardDeclared.F.decl [concrete = constants.%assoc0]
 // CHECK:STDOUT:
@@ -67,5 +67,5 @@ interface ForwardDeclared {
 // CHECK:STDOUT:   fn();
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: specific @ForwardDeclared.F(constants.%Self.9cc) {}
+// CHECK:STDOUT: specific @ForwardDeclared.F(constants.%Self.dd5) {}
 // CHECK:STDOUT: