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
Before this commit, we had effective visibility as a part of FIR status,
so it was integrated into the full pipeline. In this commit,
we introduced "effective visibility as a service" which is now used
only by exposed visibility checker. This allows us to make the thing
universal for all FIR nodes, including nodes for Java / deserialized.
Simon Ogorodnik