[libc++] Fix tests after llvm#144220

This is a backport of the test fixes made in llvm#151935

Fixes llvm#150601

Author: cor3ntin

libcxx/test/libcxx/utilities/expected/expected.expected/value.observers.verify.cpp

@@ -95,6 +95,7 @@ void test() {
       std::expected<int, CopyConstructibleButNotMoveConstructible> e;
       [[maybe_unused]] auto val = std::move(e).value();
       // expected-error-re@*:* {{static assertion failed {{.*}}error_type has to be both copy constructible and constructible from decltype(std::move(error()))}}
+      // The following diagnostic is emmitted in expected.h:
     }
   }
 
@@ -118,14 +119,16 @@ void test() {
       const std::expected<int, CopyConstructibleButNotMoveConstructible> e;
       [[maybe_unused]] auto val = std::move(e).value();
       // expected-error-re@*:* {{static assertion failed {{.*}}error_type has to be both copy constructible and constructible from decltype(std::move(error()))}}
+      // The following diagnostic is emmitted in expected.h:
     }
   }
 // These diagnostics happen when we try to construct bad_expected_access from the non copy-constructible error type.
 #if _LIBCPP_HAS_EXCEPTIONS
   // expected-error-re@*:* {{call to deleted constructor of{{.*}}}}
   // expected-error-re@*:* {{call to deleted constructor of{{.*}}}}
-  // expected-error-re@*:* 1-2{{call to deleted constructor of{{.*}}}}
-  // expected-error-re@*:* 0-2{{call to deleted constructor of{{.*}}}}
 #endif
+// These diagnostics can also additionally be produced by static_assert (see GH150601).
+// expected-error-re@*:* 0-2{{call to deleted constructor of{{.*}}}}
+// expected-error-re@*:* 0-2{{call to deleted constructor of{{.*}}}}
 }
 // clang-format on