[modules] Add testcase for a bug reduced from a selfhost issue. This bug was
never present in Clang trunk, but was present in some of my development work,
and it seems like a useful test to have.

llvm-svn: 214154
diff --git a/clang/test/Modules/cxx-templates.cpp b/clang/test/Modules/cxx-templates.cpp
index cbe9f35..b5036ff 100644
--- a/clang/test/Modules/cxx-templates.cpp
+++ b/clang/test/Modules/cxx-templates.cpp
@@ -105,6 +105,7 @@
 
   int &p = WithPartialSpecializationUse().f();
   int &q = WithExplicitSpecializationUse().inner_template<int>();
+  int *r = PartiallyInstantiatePartialSpec<int*>::bar();
 }
 
 static_assert(Outer<int>::Inner<int>::f() == 1, "");