Merge branch 'nk/perf-fsmonitor-cleanup' into maint

Test fix.

* nk/perf-fsmonitor-cleanup:
  p7519: allow running without watchman prereq

Author: gitster

t/perf/p7519-fsmonitor.sh

@@ -129,7 +129,12 @@ setup_for_fsmonitor() {
 
 	git config core.fsmonitor "$INTEGRATION_SCRIPT" &&
 	git update-index --fsmonitor 2>error &&
-	test_must_be_empty error  # ensure no silent error
+	if test_have_prereq WATCHMAN
+	then
+		test_must_be_empty error  # ensure no silent error
+	else
+		grep "Empty last update token" error
+	fi
 }
 
 test_perf_w_drop_caches () {