【内核子系统集成测试】修复不稳定的用例：fs_posix模块FsStdlibTest.cpp#testRealpath

Change-Id: If6f4237a99eceb508f2c981476d1cd57a0c96c18

kernel_lite/fs_posix/src/FsStdlibTest.cpp

@@ -120,7 +120,11 @@ HWTEST_F(FileSystemTest, testRealpath, Function | MediumTest | Level3)
     // get Absolute Path
     const char *realPathStandard = TOP_DIR "/" FILE0;
     char *realPath = (char*)malloc(256);
-    ASSERT_NE(realpath(FILE0, realPath), nullptr) << "> realpath errno = " << errno;
+    if(realpath(FILE0, realPath) == nullptr){
+        LOG("> realpath errno == %d", errno);
+        free(realPath);
+        ASSERT_TRUE(false);
+    } 
     EXPECT_STREQ(realPath, realPathStandard);
     LOG("> realPath = %s", realPath);
     free(realPath);