Remove debugging aids from this test and fix its expectations.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279034 91177308-0d34-0410-b5e6-96231b3b80d8

test/Modules/pr28438.cpp

@@ -4,6 +4,4 @@
 #include "a.h"
 #include "b2.h"
 
-#pragma clang __debug macro FOO
-
-FOO // xpected-no-diagnostics
+FOO // expected-no-diagnostics