clang accepts invalid code that with trailing comma

[hokein]

Clang doesn't diagnose the following invalid code (with the trailing comma), it treats as valid code:

void func(int);
void k() {
  func(1, );
}

This is a regression caused by #114684.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Haojian Wu (hokein)

Clang doesn't diagnose the following invalid code (with the trailing comma), it treats as valid code:

void func(int);
void k() {
  func(1, );
}

This is a regression caused by #114684.