fixed memory leaks and almost all undefined behaviour

tests/bigdict.c

@@ -70,12 +70,14 @@ int main(int argc, const char** argv)
     char* buffer = (char*)malloc(bufferSize);
     void* out = malloc(outSize);
     void* roundtrip = malloc(dataSize);
+    int _exit_code = 0;
     (void)argc;
     (void)argv;
 
     if (!buffer || !out || !roundtrip || !cctx || !dctx) {
         fprintf(stderr, "Allocation failure\n");
-        return 1;
+        _exit_code = 1;
+        goto cleanup;
     }
 
     if (ZSTD_isError(ZSTD_CCtx_setParameter(cctx, ZSTD_c_windowLog, 31)))
@@ -119,10 +121,13 @@ int main(int argc, const char** argv)
 
     fprintf(stderr, "Success!\n");
 
+    goto cleanup;
+
+cleanup:
     free(roundtrip);
     free(out);
     free(buffer);
-    ZSTD_freeDCtx(dctx);
     ZSTD_freeCCtx(cctx);
-    return 0;
+    ZSTD_freeDCtx(dctx);
+    return _exit_code;
 }