stdlib/NSString APIs on String: add more tests and fix a crash in _countFormatSpecifiers() that was triggered by non-BMP characters in the format string
stdlib/NSString APIs on String: add more tests and fix a crash in
_countFormatSpecifiers() that was triggered by non-BMP characters in the format
string


Swift SVN r21014

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