tests: make test-verify-repo-operations.py not run by default

test-verify-repo-operations.py currently starts way too late and
extends the running time with -j50 on my machine from around 3:48 min
to 6:30 min. We could of course make it run earlier, but the test case
seems unlikely to find bugs not covered by other tests, so let's mark
it "slow" instead. I think this type of test is better suited to
running separately in a long-running job.

tests/test-verify-repo-operations.py

@@ -7,8 +7,14 b' operations and test Mercurial using them'
 unexpected errors and to compare different versions of it."""
 
 import os
+import subprocess
 import sys
 
+# Only run if slow tests are allowed
+if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'],
+                    'slow']):
+    sys.exit(80)
+
 # These tests require Hypothesis and pytz to be installed.
 # Running 'pip install hypothesis pytz' will achieve that.
 # Note: This won't work if you're running Python < 2.7.