RFR 8134873: Implement support for ES6 numeric literals

[Andreas Woess]

Please reviewhttp://cr.openjdk.java.net/~aw/8134873/  forhttps://bugs.openjdk.java.net/browse/JDK-8134873

Implements Lexer/Parser support for ECMAScript 6 binary (0b) and octal (0o) literals. I've renamed OCTAL (legacy octal literal, e.g. 0777) to OCTAL_LEGACY and added OCTAL and BINARY_LITERAL token types (the _LITERAL suffix is to disambiguate with TokenKind.BINARY).

Thanks,
Andreas