[clang] [Clang] Implement P3074R7: trivial unions (C++26) (PR #185886)

[Vlad Serebrennikov via cfe-commits]

================
@@ -1,18 +1,18 @@
 // RUN: %clang_cc1 -std=c++98 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected
-// RUN: %clang_cc1 -std=c++11 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,cxx11-17,since-cxx11
-// RUN: %clang_cc1 -std=c++14 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,cxx14-17,cxx11-17,since-cxx11,since-cxx14
-// RUN: %clang_cc1 -std=c++17 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,cxx14-17,cxx11-17,since-cxx11,since-cxx14
-// RUN: %clang_cc1 -std=c++20 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,since-cxx11,since-cxx14,since-cxx20
-// RUN: %clang_cc1 -std=c++23 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,since-cxx11,since-cxx14,since-cxx20
-// RUN: %clang_cc1 -std=c++2c %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,since-cxx11,since-cxx14,since-cxx20
+// RUN: %clang_cc1 -std=c++11 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,cxx11-17,since-cxx11,precxx26
----------------
Endilll wrote:

```suggestion
// RUN: %clang_cc1 -std=c++11 %s -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected,cxx11-17,since-cxx11,cxx11-23
```

https://github.com/llvm/llvm-project/pull/185886