Fix incorrect detection of class definitions with alignas specification.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192094 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 85813bc..6bb38e9 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -4468,6 +4468,7 @@
   verifyFormat("class __attribute__(X) Z {\n} n;");
   verifyFormat("class __declspec(X) Z {\n} n;");
   verifyFormat("class A##B##C {\n} n;");
+  verifyFormat("class alignas(16) Z {\n} n;");
 
   // Redefinition from nested context:
   verifyFormat("class A::B::C {\n} n;");