Enable fast tracepoint tests

Enable fast tracepoint tests

gdb/testsuite/ChangeLog:

	* gdb.trace/change-loc.h (func4) [__aarch64__]: Add a nop
	instruction.
	* gdb.trace/pendshr1.c (pendfunc): Likewise.
	* gdb.trace/pendshr2.c (pendfunc2): Likewise.
	* gdb.trace/range-stepping.c: Likewise.
	* gdb.trace/trace-break.c: Likewise.
	* gdb.trace/trace-mt.c (thread_function): Likewise.
	* gdb.trace/ftrace.c (marker): Likewise.
	* gdb.trace/trace-condition.c (marker): Likewise.
	* gdb.trace/ftrace.exp: Enable ftrace test if is_aarch64_target.
	* gdb.trace/trace-condition.exp: Set pcreg to "\$pc" if
	is_aarch64_target.