i#1569 AArch64: Use PTRACE_GETREGSET and PTRACE_SETREGSET.
i#1569 AArch64: Use PTRACE_GETREGSET and PTRACE_SETREGSET.

PTRACE_GETREGS and PTRACE_SETREGS are not available on arm64 so use
PTRACE_GETREGSET and PTRACE_SETREGSET instead.
This code is currently not tested.

Review-URL: https://codereview.appspot.com/292870043

AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio