gdb/aarch64: Test record/replay support for CSSC

GDB can handle AArch64's CSSC instructions but there were no tests
ensuring that and ensuring no regressions would creep in. This commit
adds some tests for these instructions. This was tested on
aarch64-none-linux-gnu on QEMU with CSSC support.

Approved-By: Guinevere Larsen <guinevere@redhat.com>