oeqa/concurrencytest: Optimise for autobuilder/clobberdir

We're seeing huge delays on the autobuilder during oe-selftest builddir
deletion. For example there is a currently running selftest we could do
with the results from and its been going 13 hours, at least 8 of which
was in deletion of the builddirs.

There are a variety of ways we could solve this problem however the
autobuilder has a mechanism for deferred deletion, "clobberdir" which
it already uses for this kind of work.

Whilst in general hardcoding things like this is horrible, I believe
in this case the benefits (and resulting improvements on my sanity
if nothing else) mean this is a case where we should do it.

If/as/when someone can come up with a better solution that is fine
and this can be replaced.

(From OE-Core rev: 51a84937d32a85cbdb7d5b1d1ec69a290d0c303b)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/core/utils/concurrencytest.py

@@ -221,6 +221,15 @@ def removebuilddir(d):
     while delay and os.path.exists(d + "/bitbake.lock"):
         time.sleep(1)
         delay = delay - 1
+    # Deleting these directories takes a lot of time, use autobuilder
+    # clobberdir if its available
+    clobberdir = os.path.expanduser("~/yocto-autobuilder-helper/janitor/clobberdir")
+    if os.path.exists(clobberdir):
+        try:
+            subprocess.check_call([clobberdir, d])
+            return
+        except subprocess.CalledProcessError:
+            pass
     bb.utils.prunedir(d, ionice=True)
 
 def fork_for_tests(concurrency_num, suite):