patch 9.0.0574: timer garbage collect test hangs on Mac M1

Problem:    Timer garbage collect test hangs on Mac M1.
Solution:   Properly check for Mac M1 and skip the test.

src/testdir/test_timers.vim

@@ -381,7 +381,12 @@ endfunc
 " vgetc().
 func Test_nocatch_timer_garbage_collect()
   " FIXME: why does this fail only on MacOS M1?
-  CheckNotMacM1
+  try 
+    CheckNotMacM1
+  catch /Skipped/
+    let g:skipped_reason = v:exception
+    return
+  endtry
 
   " 'uptimetime. must be bigger than the timer timeout
   set ut=200

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    574,
 /**/
     573,
 /**/