Add standalone cases (#3536)

tests/standalone/test-strchr/main.c

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2019 Intel Corporation.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main(int argc, char **argv)
+{
+    char *str = malloc(32);
+    printf("str ptr: %p\n", str);
+
+    sprintf(str, "%s", "123456");
+    printf("str: %s\n", str);
+
+    char *str1 = strchr(str, '3');
+    printf("str1 ptr: %p\n", str1);
+    printf("str1: %s\n", str1);
+
+    free(str);
+    return 0;
+}