Workaround poor reparse test performance and #1240

[timsueberkrueb]

There are two issues related to the core reparse tests that currently slow down our development:

1. They take a long time to execute because the core parser is very slow. The full test suite currently takes ~13m in CI
2. Since separating out the reparse tests from the rest of the test suite we sometimes see long-running (likely diverging) test execution (see Investigate long running "Internal Tests & Verify Binary" CI #1240). The exact cause is still unclear, but I hypothesize the issue will disappear by reverting this change.

This PR

• runs reparse tests only on the "benchmarks" subset of the full test suite
• reverts the separation of the reparse test from the remaining internal tests

[phischu]

Yes, I think this amount of testing is sufficient.

[timsueberkrueb]

With this PR, runtime for the internal tests still increases from ~3.5m to 7m. I could select an even smaller subset if you like.

[jiribenes]

LGTM

[jiribenes]

I just noticed this in #1170 cc @timsueberkrueb

[jiribenes]

... oh, separateTests has "effekt.StdlibChezCPSTests",
but it's stdlibchezSCHEMEcpstests.

=> #1274