clang-format: Fix incorrect macro call detection.

In:
  struct A {
    A()
        noexcept(....) {}
  };

'A()' is not a macro call.
This fixes llvm.org/PR19814.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209294 91177308-0d34-0410-b5e6-96231b3b80d8