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

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

Change-Id: Ib917bc4e168bdb8846b324e845c85035f06dc668