Mark a struct definition in an objc container with the TopLevelDeclInObjCContainer bit.

Fixes accurately getting a cursor inside an objc container containing a struct definition,
from a PCH/preamble file.

rdar://12584613

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173811 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Index/getcursor-preamble.h b/test/Index/getcursor-preamble.h
new file mode 100644
index 0000000..519e655
--- /dev/null
+++ b/test/Index/getcursor-preamble.h
@@ -0,0 +1,8 @@
+@interface I {
+  struct AA {
+    int x;
+  } aa;
+  int var;
+}
+-(id)foo;
+@end