Fix crash in libclang if code completion is used with unknown flags.

Use CaptureDroppedDiagnostics to make sure that there is a diagnostic
client installed when warning flags are parsed.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@186582 91177308-0d34-0410-b5e6-96231b3b80d8
clang-format: Fix bad line break with pointers to members.

Before:
  void f() {
    (a->*
     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)(aaaa,
                                           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
  }

After:
  void f() {
    (a->*aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)(
        aaaa, bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
  }

Also add missing test case.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@186583 91177308-0d34-0410-b5e6-96231b3b80d8
Replacing a morally duplicate diagnostic by adding it to an existing diagnostic's select list.  Updates the tests for the more consistent diagnostic.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@186584 91177308-0d34-0410-b5e6-96231b3b80d8