Many of the regexes and bits in the task config assume that ccov will be the last dash-separated piece of the test platform. i.e. windows10-64-ccov rather than than windows10-64-ccov-foo. In bug 1669478 we want to add some ccov jobs with webrender enabled, which we've generally indicated by having -qr in the test platform name. So we can either do windows10-64-ccov-qr or windows10-64-qr-ccov. I prefer the former because it follows the implicit convention of "least modifiable first" (i.e. ccov is a build-time option, whereas qr is a run-time option, and therefore more modifiable). Either way will require fiddling with a bunch of regexes so in terms of code changes it's about the same amount of work.

I need to modify the ccov regexes to allow additional suffixes. The negative-
search regex makes this hard, and seems quite complex/error-prone. Instead of the
negative-search regex, we can accomplish the same thing by splitting out a
new test-set.

Note that with this patch, there are a handful of jobs that get removed from
the list generated by ./mach taskgraph full (listed below). I believe this
is a desirable change since per the comment in the code it seems like we don't
want these jobs to run. In fact, I don't see these jobs on TreeHerder, so maybe
some other step is pruning them out anyway.

The jobs being removed are below. The '' at the end represents the chunk number,
each of the labels with a '' has 6 chunks which I've collapsed into a single
label for brevity.

test-linux1804-64-asan/opt-jittest-1proc-*
test-linux1804-64/debug-jittest-1proc-*
test-linux1804-64-devedition/opt-jittest-1proc-*
test-linux1804-64/opt-jittest-1proc-*
test-linux1804-64-qr/debug-jittest-1proc-*
test-linux1804-64-qr/opt-jittest-1proc-*
test-linux1804-64-shippable/opt-jittest-1proc-*
test-linux1804-64-shippable-qr/opt-jittest-1proc-*
test-windows10-64-asan/opt-jittest-1proc
test-windows10-64/debug-jittest-1proc
test-windows10-64-devedition/opt-jittest-1proc
test-windows10-64/opt-jittest-1proc
test-windows10-64-shippable/opt-jittest-1proc
test-windows7-32/debug-jittest-1proc
test-windows7-32/opt-jittest-1proc
test-windows7-32-shippable/opt-jittest-1proc

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.

Depends on D94723

This allows additional suffixes (e.g. -qr) to be added to ccov test platforms,
and in most cases those labels will be treated the same as the other ccov jobs.
In a few cases exact (non-regex) keys were left unmodified, because changing
a non-regex key to a regex key can result in taskgraph generation failure, if
more than one regex key matches.

I verified that this patch does not modify the output generated by ./mach taskgraph full --json.

Depends on D94724

https://hg.mozilla.org/mozilla-central/rev/2c1ed7709fb1
https://hg.mozilla.org/mozilla-central/rev/4952ca247c61
https://hg.mozilla.org/mozilla-central/rev/585afaeeb310