Fix comments before labels.

Before:
switch (...) {
  // a
  // b
// c
case first:
  break;
}

After:
switch (...) {
// a
// b
// c
case first:
  break;
}

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179107 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index cb28a4f..4585ac2 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -432,6 +432,7 @@
                "  // Do nothing.\n"
                "}");
   verifyFormat("switch (x) {\n"
+               "// comment\n"
                "// if 1, do f()\n"
                "case 1:\n"
                "  f();\n"