iOS buildbot failure comments don't contain failure details anymore

[mhsmith]

Specificially, they don't contain:

• The names of the failed tests
• The tracebacks

It looks like this changed in December 2024, probably because the test script was updated to add a prefix to every log line. The relevant regexes are here.

Before:

• Add a --rerun option to the iOS testbed. #122992 (comment)
• gh-116510: Fix crash due to shared immortal interned strings. #124646 (comment)

After:

• gh-128923: Use zero to indicate unassigned unique id #128925 (comment)
• gh-127085: Fix memoryview->exports race condition. #127412 (comment)

@freakboy3742: FYI

Linked PRs

• gh-129248: Filter out the iOS log prefix from testbed runner output. #129252
• [3.13] gh-129248: Filter out the iOS log prefix from testbed runner output. (GH-129252) #129283

[freakboy3742]

Yeah - this will be a result of #127592. The log prefix doesn't really help diagnose anything, so I'll strip it (matching what Android does with its logger).