Auto merge of #113389 - Zalathar:re-enable, r=Mark-Simulacrum

Re-enable some coverage tests on Linux

These tests were originally disabled (on all platforms) in #110393, because those changes had made them start failing on Linux for unclear reasons.

I tried to re-enable them unconditionally in #111179, since they worked locally on my Mac, but I found that they were still failing on Linux, so I gave up at that time.

Later while working on #112300 I was able to re-enable them on Windows and Mac, since those changes made it possible to add specific `ignore-` directives to individual tests. I noticed at the time that the tests actually seemed to be working again on Linux, but by that point I didn't want to risk more CI failures, so I left them disabled on Linux with an intention to re-enable them later.

Now I'm going back to re-enable them on Linux too, since they seem to work fine.

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Because `run-coverage` tests are sensitive to line numbers, and `x test tidy` doesn't like leading blank lines, I've replaced the old comment/ignore with an informative comment that occupies the same number of lines.

Author: bors