tests/test-hgwebdir-gc.py

tests: fix glob pattern for dynamic timer alignment

The number of space characters varies depending on the number of digits of the
timer, making some tests fail on slow machines in an unintended way:

```diff
--- /build/mercurial-6.1/tests/test-merge-halt.t
+++ /build/mercurial-6.1/tests/test-merge-halt.t.err
@@ -210,6 +210,6 @@
   merge halted after failed merge (see hg resolve)
   [240]
   $ hg shelve --list
-  default         (* ago)    changes to: foo (glob)
+  default         (11s ago)   changes to: foo
   $ hg unshelve --abort
   unshelve of 'default' aborted
ERROR: test-merge-halt.t output changed
```

Differential Revision: https://phab.mercurial-scm.org/D12381

import os
from mercurial.hgweb import hgwebdir_mod

hgwebdir = hgwebdir_mod.hgwebdir

os.mkdir(b'webdir')
os.chdir(b'webdir')

webdir = os.path.realpath(b'.')


def trivial_response(req, res):
    return []


def make_hgwebdir(gc_rate=None):
    config = os.path.join(webdir, b'hgwebdir.conf')
    with open(config, 'wb') as configfile:
        configfile.write(b'[experimental]\n')
        if gc_rate is not None:
            configfile.write(b'web.full-garbage-collection-rate=%d\n' % gc_rate)
    hg_wd = hgwebdir(config)
    hg_wd._runwsgi = trivial_response
    return hg_wd


def process_requests(webdir_instance, number):
    # we don't care for now about passing realistic arguments
    for _ in range(number):
        for chunk in webdir_instance.run_wsgi(None, None):
            pass


without_gc = make_hgwebdir(gc_rate=0)
process_requests(without_gc, 5)
assert without_gc.requests_count == 5
assert without_gc.gc_full_collections_done == 0

with_gc = make_hgwebdir(gc_rate=2)
process_requests(with_gc, 5)
assert with_gc.requests_count == 5
assert with_gc.gc_full_collections_done == 2

with_systematic_gc = make_hgwebdir()  # default value of the setting
process_requests(with_systematic_gc, 3)
assert with_systematic_gc.requests_count == 3
assert with_systematic_gc.gc_full_collections_done == 3