[c-index-test] Suppress -Wcast-qual after D153911

[MaskRay]

Summary

free_remapped_files needs to discard the casts qualifier.
index_startedTranslationUnit casts a string literal to void *.

Since we probably cannot change the public API, suppress the warnings.

[MaskRay]

commit 0f0c3d45d7d75ba82a955246da654146a7d57a0d did this first

clang/tools/c-index-test/c-index-test.c

if (Err != CXError_Success) {
     return 0;
   }
   return 1;
 }
 
 void free_remapped_files(struct CXUnsavedFile *unsaved_files,
                          int num_unsaved_files) {
   int i;
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-qual"
+#endif
   for (i = 0; i != num_unsaved_files; ++i) {
     free((char *)unsaved_files[i].Filename);
     free((char *)unsaved_files[i].Contents);
   }
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
   free(unsaved_files);
 }
 
 static int parse_remapped_files_with_opt(const char *opt_name,
                                          int argc, const char **argv,
                                          int start_arg,
                                          struct CXUnsavedFile **unsaved_files,
                                          int *num_unsaved_files) {

 
 static CXIdxClientContainer
 index_startedTranslationUnit(CXClientData client_data, void *reserved) {
   IndexData *index_data;
   index_data = (IndexData *)client_data;
   printCheck(index_data);
 
   printf("[startedTranslationUnit]\n");
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-qual"
+#endif
   return (CXIdxClientContainer)"TU";
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
 }
 
 static void index_indexDeclaration(CXClientData client_data,
                                    const CXIdxDeclInfo *info) {
   IndexData *index_data;
   const CXIdxObjCCategoryDeclInfo *CatInfo;
   const CXIdxObjCInterfaceDeclInfo *InterInfo;
   const CXIdxObjCProtocolRefListInfo *ProtoInfo;