vim-patch:9.0.1881: Test_crash fails on Mac

Problem:  Test_crash fails on Mac
Solution: Skip test on Mac

5856b07795

Co-authored-by: Christian Brabandt <cb@256bit.org>

test/old/testdir/test_crash.vim

@@ -7,6 +7,8 @@ CheckScreendump
 func Test_crash1()
   CheckNotBSD
   CheckExecutable dash
+  " Test 7 fails on Mac ... 
+  CheckNotMac
 
   " The following used to crash Vim
   let opts = #{cmd: 'sh'}