[libclang] Add missing return in clang_getExpansionLocation that resulted in that function
always returning a null file/line/column.

Also add at least one use of clang_getExpansionLocation inside c-index-test that would have
made the tests to catch that.

llvm-svn: 143606
diff --git a/clang/tools/libclang/CXSourceLocation.cpp b/clang/tools/libclang/CXSourceLocation.cpp
index 7138344..d8d4c96 100644
--- a/clang/tools/libclang/CXSourceLocation.cpp
+++ b/clang/tools/libclang/CXSourceLocation.cpp
@@ -212,6 +212,7 @@
       *column = SM.getExpansionColumnNumber(ExpansionLoc);
     if (offset)
       *offset = SM.getDecomposedLoc(ExpansionLoc).second;
+    return;
   }
   
   // FIXME: