Bug 1325801 - Fix intermittent failure staging cppunittests. r=mshal

Dumping symbols can interfere with staging cppunittests in case calling
objcopy from the symbol dumping script coincides exactly with calling
objcopy when staging cppunittests when the two are run in parallel. This
patch prevents symbol dumping from happening while tests are being packaged.

MozReview-Commit-ID: Hgi1zyIZE7K

--HG--
extra : rebase_source : 5fac1ff8aeacde38e27ca0ca7f33ed9a594dc06b

build/moz-automation.mk

@@ -78,6 +78,11 @@ automation/upload: automation/buildsymbols
 automation/upload: automation/update-packaging
 automation/upload: automation/sdk
 
+# buildsymbols will modify our test binaries, which can interfere with
+# packaging them. A finer-grained dependency can help performance here
+# once bug 1329020 is fixed.
+automation/pretty-package-tests: automation/buildsymbols
+
 # automation/{pretty-}package should depend on build (which is implicit due to
 # the way client.mk invokes automation/build), but buildsymbols changes the
 # binaries/libs, and that's what we package/test.