I get a 100% reproducible test failure when running ./mach mochitest-plain layout/mathml/tests on my build: ERROR TEST-UNEXPECTED-FAIL | /tests/layout/mathml/tests/test_bug553917.html | Assertion count 208 is greater than expected range 204-204 assertions.
The assertions are all of the form: ###!!! ASSERTION: FormatStringFromName() without format parameters: use GetStringFromName() instead: 'aParams && aLength', file /home/catalin/hacking/moz/mozilla-central/intl/strres/src/nsStringBundle.cpp, line 186
Created attachment 740073 [details] [diff] [review] Patch that removes all assertions This patch gets rid of all the assertions by using nsIStringBundle.GetStringFromName instead of nsIStringBundle.formatStringFromName when the format parameters are an empty list. I don't really know the assertion gets triggered on my machine 208 times instead of 204 on the test machines, but it seems better to get rid of the assertion anyway and use the appropriate method of nsIStringBundle.
Adding checkin-needed following karlt's review+