btrace: check if we're replaying when setting the replay position to the end

btrace: check if we're replaying when setting the replay position to the end

When setting the replay position to the end there is nothing to do if we are
not replaying.  Check that and return immediately.

This avoids printing the current location if we're already at the end.

Signed-off-by: Markus Metzger  <markus.t.metzger@intel.com>
gdb/
	* record-btrace.c (record_btrace_set_replay): Check if replaying.

testsuite/
	* gdb.btrace/record_goto.exp: Test "record goto end" twice.

Change-Id: I4878892408bab293261bbea40d6af28440ff3ec5