Start doing more validation of intrinsics: assert, new, delete, rand (#2766)

This is adding more validation of intrinsics. It addresses a bug in rand where CHECK-fails would occur for bad range inputs, instead of a runtime error. I'm also addressing what I think was an int32 range issue in the handling by running the generator with int64.

explorer/testdata/pointer/fail_delete_uninit.carbon

@@ -0,0 +1,16 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// RUN: %{not} %{explorer-run}
+// RUN: %{not} %{explorer-run-trace}
+
+package ExplorerTest api;
+
+fn Main() -> i32 {
+  var p: i32*;
+  // CHECK:STDERR: RUNTIME ERROR: {{.*}}/explorer/testdata/pointer/fail_delete_uninit.carbon:[[@LINE+1]]: undefined behavior: access to uninitialized value Uninit<Placeholder<p>>
+  heap.Delete(p);
+  return 0;
+}

explorer/testdata/pointer/fail_intrinsic_delete_no_args.carbon

@@ -0,0 +1,15 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// RUN: %{not} %{explorer-run}
+// RUN: %{not} %{explorer-run-trace}
+
+package ExplorerTest api;
+
+fn Main() -> i32 {
+  // CHECK:STDERR: COMPILATION ERROR: {{.*}}/explorer/testdata/pointer/fail_intrinsic_delete_no_args.carbon:[[@LINE+1]]: __intrinsic_delete takes 1 argument
+  __intrinsic_delete();
+  return 0;
+}

explorer/testdata/pointer/fail_intrinsic_delete_type.carbon

@@ -0,0 +1,18 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// RUN: %{not} %{explorer-run}
+// RUN: %{not} %{explorer-run-trace}
+
+package ExplorerTest api;
+
+fn Main() -> i32 {
+  var x: i32;
+  // CHECK:STDERR: COMPILATION ERROR: {{.*}}/explorer/testdata/pointer/fail_intrinsic_delete_type.carbon:[[@LINE+3]]: type error in *
+  // CHECK:STDERR: expected a pointer type
+  // CHECK:STDERR: actual: i32
+  __intrinsic_delete(x);
+  return 0;
+}

explorer/testdata/pointer/fail_intrinsic_new_no_args.carbon

@@ -0,0 +1,15 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// RUN: %{not} %{explorer-run}
+// RUN: %{not} %{explorer-run-trace}
+
+package ExplorerTest api;
+
+fn Main() -> i32 {
+  // CHECK:STDERR: COMPILATION ERROR: {{.*}}/explorer/testdata/pointer/fail_intrinsic_new_no_args.carbon:[[@LINE+1]]: __intrinsic_new takes 1 argument
+  __intrinsic_new();
+  return 0;
+}

explorer/testdata/pointer/new_and_delete_class.carbon

@@ -0,0 +1,23 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// RUN: %{explorer-run}
+// RUN: %{explorer-run-trace}
+// CHECK:STDOUT: result: 0
+
+package ExplorerTest api;
+
+class C {
+  fn DoPrint() { Print("test"); }
+}
+
+fn Main() -> i32 {
+  var p: auto = heap.New(C);
+  var y: auto = *p;
+  // The following line would fail with: "could not find `y: auto`"
+  // y.DoPrint();
+  heap.Delete(p);
+  return 0;
+}

explorer/testdata/pointer/new_and_delete_fn.carbon

@@ -0,0 +1,21 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// AUTOUPDATE
+// RUN: %{explorer-run}
+// RUN: %{explorer-run-trace}
+// CHECK:STDOUT: test
+// CHECK:STDOUT: result: 0
+
+package ExplorerTest api;
+
+fn F() { Print("test"); }
+
+fn Main() -> i32 {
+  var p: auto = heap.New(F);
+  var y: auto = *p;
+  y();
+  heap.Delete(p);
+  return 0;
+}