Bug 1095298 - Ignore 'C' locale when initializing nsLocaleService on Android. r=emk, a=lmandel

On Android Lollipop, our setlocale call returns "C", rather than the null it returns on earlier Android versions.

This impacts locale detection, causing devices to always appear to be in en-US.

This patch conditionally ignores "C" if MOZ_WIDGET_ANDROID is set.
Bug 1093278 - Null check in nsPurpleBuffer::VisitEntries. r=smaug, a=lmandel
Bug 1096263 - XMLHttpRequest.send({}) should not throw. r=bz, a=lmandel
Bug 1096263 - XMLHttpRequest.send({}) should not throw, tests. r=bz, a=lmandel
Bug 1096263 - We pass now this XHR wp test. a=lmandel