Extend timeout-minutes for macOS --repeat-count=2

https://github.com/ruby/ruby/actions/runs/17308244022/job/49136485007

I'm not sure if it's stuck forever at the end or happens to take that
much time around the end of it, but let me just try this first.

If it doesn't work, something's wrong with --repeat-count=2 on test-all.

Author: k0kubun

.github/workflows/macos.yml

@@ -141,7 +141,7 @@ jobs:
 
           ulimit -c unlimited
           make -s ${{ matrix.test_task }} ${TESTS:+TESTS="$TESTS"}
-        timeout-minutes: 60
+        timeout-minutes: 90
         env:
           RUBY_TESTOPTS: '-q --tty=no'
           TEST_BUNDLED_GEMS_ALLOW_FAILURES: ''