How to update long checks

[Gavin Smith]

I had to update some of the long tests in tp/tests, but I didn't find
the instructions very clear. I ended up running commands like

cp coverage//out_parser_info/formatting_fr/formatting.info
coverage//res_parser_info/formatting_fr/formatting.info

I tried running "../run_parser_all -copy" from within the "coverage"
directory, but it did nothing.

Why is there a separate directory "staging_res" for the results, e.g.
coverage//diffs/staging_res and "out_parser_info"?

I didn't try "./long-checks.sh -copy" because my attempt to use
long-checks.sh to run a single test "LONG_CHECKS=yes ./long-checks.sh
coverage" ran the test I specified, and then ran them all; and I
didn't want to regenerate all the test results at once.

(I wrote this email a while ago but didn't send it in case I found
something else to add.)