Update includes:
- Changing syntax of `OI/`NI` tags from `<!NI;TAG!>` to `<!TAG{NI}!>`
- Fix some incorrect directives
- Change order of diagnostics in some places
- Remove ignored diagnostics from FIR test data (previously `DIAGNOSTICS` didn't work)
- Update FIR dumps in some places and add `FIR_IDENTICAL` if needed
- Replace all JAVAC_SKIP with SKIP_JAVAC directive
It has been done just to avoid clashes with real declarations that look
like our builtins: e.g. 'String removeAt(int index) {}' and 'String remove(int index) {}'in Java.
But synthesized members are even weaker than extensions.
Solution is just to ignore the latter declaration and treat first as effective override
of out builltin.
Dmitriy Novozhilov