[javasrc2cpg] add basic static field test

[xavierpinho]

Apropos #5049, includes an ignored test that stopped working after #5036. Unfortunately, such a test wasn't there before to flag this regression.

Previously, in the example's System.out.println(CONST) we were lowering CONST as Bar.CONST, with Bar an IDENTIFIER. Presently, Bar is a TYPE_REF and we lose this dataflow.

Another thing to point out regarding this design change is that it's not consistent throughout. For instance, if we had written System.out.println(Bar.CONST) , Bar is here not a TYPE_REF but again an IDENTIFIER.

I'm willing to contribute patch(es) to the recovery of this flow, but would need some guidance as I've not been able to find a workaround after some initial experiments. (Thanks in advance)

[johannescoetzee]

Good catch! I don't have much experience with the OSS dataflow engine so can't say much there, but I agree we should update the explicit Bar.CONST case as well. I'll add it to my TODO list for when I'm done with pattern matching support