Change HIDL fmq tests to use int32_t for payload am: 0a10d6918c am: 606d2ec362 am: 5b1514cb70 am: 913bfbf823 am: 27931d55b0

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/1431692

Change-Id: I1986777ac3e722c50471106bafed07d95d023040