clang-format: Fix behavior around pointer-to-member invocations.

Before:
  (aaaaaaaaaa->*
   bbbbbbb)(aaaaaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaa));

After:
  (aaaaaaaaaa->*bbbbbbb)(
      aaaaaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaa));

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212617 91177308-0d34-0410-b5e6-96231b3b80d8