Bug 1673359 - Replace regex complexity with more fixed list. r=ahal

As with the previous patch, the negative regex makes changes hard. This replaces
the negative regex with a positive list of matching labels, similar to the one
a few lines down. I verified that this patch does not modify the output for
`./mach taskgraph full --json`.

Differential Revision: https://phabricator.services.mozilla.com/D94724

taskcluster/ci/test/xpcshell.yml

@@ -51,14 +51,14 @@ xpcshell:
         by-test-platform:
             .*-ccov/.*: 6
             android-em-7.*: 4
-            macosx.*(?!-ccov)...../.*: 2
+            macosx1014-64(-shippable|-devedition|-asan)?(-qr)?/.*: 2
             linux1804-64(-qr)?/debug: 6
             .*-tsan/opt: 8
             windows(7-32|10-64)(-shippable|-devedition|-asan|.*-qr)?/.*: 2
             default: 5
     max-run-time:
         by-test-platform:
-            macosx.*(?!-ccov)...../.*: 5400
+            macosx1014-64(-shippable|-devedition|-asan)?(-qr)?/.*: 5400
             windows(7-32|10-64)(-shippable)?/opt: 5400
             .*-ccov/.*: 7200
             .*-tsan/opt: 7200