tests: allow a long test to have more time to complete before timing out

This test is intended to test really long output, so it prints 100k
lines of stdout/stderr. It completes in two seconds on my machine, but
the default 30-second timeout is apparently too much for CI, because on
Windows we often get flaky tests due to this. e.g. we'll get within 200
lines of the end.

Bump the CI time by x2. We know this isn't particularly surprising
behavior, and allowing it to request another 30 seconds won't hang the
CI. But it will save us from some spurious failures and restarted jobs.

test cases/common/254 long output/meson.build

@@ -1,5 +1,5 @@
 project('long-stderr', 'c')
 
 dumper = executable('dumper', 'dumper.c')
-test('dump-test', dumper)
-test('dump-test-TAP', dumper, protocol : 'tap')
+test('dump-test', dumper, timeout: 60)
+test('dump-test-TAP', dumper, protocol : 'tap', timeout: 60)