[android] Enable NumberFormatter test that actually works on Android.
[android] Enable NumberFormatter test that actually works on Android.

The original commit doesn't state why the test in particular was
disabled, but in my tests (AArch64), the test seems to work.

apple/swift-corelibs-foundation,e78l/swift-corelibs-foundation,e78l/swift-corelibs-foundation,e78l/swift-corelibs-foundation,e78l/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,e78l/swift-corelibs-foundation,apple/swift-corelibs-foundation