Add a test case for PR8385.

"struct{template struct{" would fail an assertion.

This assertion failure seems to have gone away somewhere along the line so
here's a test to make sure we don't regress. We still accept some very weird
explicit template 'instantiations' ("template int;", anyone) but at least we're
not asserting/crashing here.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152681 91177308-0d34-0410-b5e6-96231b3b80d8

test/SemaCXX/PR8385.cpp

@@ -0,0 +1,7 @@
+// RUN: not %clang_cc1 -fsyntax-only %s
+
+// don't crash on this, but don't constrain our diagnostics here as they're
+// currently rather poor (we even accept things like "template struct {}").
+// Other, explicit tests, should verify the relevant behavior of template 
+// instantiation.
+struct{template struct{