[Clang][NFC] Remove a redundancy check in Sema::adjustMemberFunctionCC

[xgupta]

Summary

If the current calling convection CurCC is not equal to Target calling
convection ToCC and current calling convention (CurCC) is equal to the
default calling convention (DefaultCC), that means DefaultCC can not be
equal to ToCC so the right part of the expression DefaultCC == ToCC is
not needed.

revelant code -

if (CurCC == ToCC)
  return;
if (CurCC != DefaultCC || DefaultCC == ToCC)
  return;

Found by PVS-Studio - https://pvs-studio.com/en/blog/posts/cpp/1003/, N41.

[tbaeder]

LGTM, assuming the pre-commit CI failures are unrelated.

[xgupta]

In D142338#4073826, @tbaeder wrote:

LGTM, assuming the pre-commit CI failures are unrelated.

Yeah, those 3 test cases should be unrelated, this is an nfc change.

clang/lib/Sema/SemaType.cpp

void Sema::adjustMemberFunctionCC(QualType &T, bool IsStatic, bool IsCtorOrDtor,
   // Default adjustment.
   } else {
     // Only adjust types with the default convention.  For example, on Windows
     // we should adjust a __cdecl type to __thiscall for instance methods, and a
     // __thiscall type to __cdecl for static methods.
     CallingConv DefaultCC =
         Context.getDefaultCallingConvention(IsVariadic, IsStatic);
 
-    if (CurCC != DefaultCC || DefaultCC == ToCC)
+    if (CurCC != DefaultCC)
       return;
 
     if (hasExplicitCallingConv(T))
       return;
   }
 
   FT = Context.adjustFunctionType(FT, FT->getExtInfo().withCallingConv(ToCC));
   QualType Wrapped = Unwrapped.wrap(*this, FT);