Set default C++ level for PlayStation(r) to C++17.

[probinson]

The value of a separate test for PS4/PS5 is questionable, now that it's the same as the general Clang default.
Probably better to delete lang-std-sie.cpp and remove the UNSUPPORTED from lang-std.cpp ?

[probinson]

(Also remove the now-incorrect comment from lang-std.cpp)

[Sunil_Srivastava]

Deleted Sie specific test, now that the behavior is same as the default.

[probinson]

Huh. It looks like someone else removed that stuff from lang-std.cpp recently. I'd have thought that would cause a failure on our bot, but whatever.
LGTM.

clang/lib/Basic/LangStandards.cpp

if (T.isPS4())
       return LangStandard::lang_gnu99;
     return LangStandard::lang_gnu17;
   case Language::ObjC:
     return LangStandard::lang_gnu11;
   case Language::CXX:
   case Language::ObjCXX:
   case Language::CUDA:
   case Language::HIP:
-    if (T.isPS())
-      return LangStandard::lang_gnucxx14;
     return LangStandard::lang_gnucxx17;
   case Language::RenderScript:
     return LangStandard::lang_c99;
   case Language::HLSL:
     return LangStandard::lang_hlsl2021;
   }
   llvm_unreachable("unhandled Language kind!");
 }

clang/test/Preprocessor/lang-std-sie.cpp

-/// Test that PS4/PS5 defaults to gnu++14.
-
-// RUN: %clang_cc1 -dM -E -triple x86_64-scei-ps4 %s | FileCheck --check-prefix=CXX14 %s
-// RUN: %clang_cc1 -dM -E -triple x86_64-sie-ps5 %s | FileCheck --check-prefix=CXX14 %s
-
-// CXX14: #define __cplusplus 201402L