r300: rework compile error reporting

This ports r300 from reporting the compile errors in finalize_nir to the new way introduced in dc1b719e.

First commit moves the current reporting of unsupported control flow on R300/R400, there should be no functional change. We also do no longer set call_finalize_nir_in_linker. The second commit extends the reporting to all compiler errors, including too many instructions, TEX indirections, etc...