fix: drop no-longer-necessary half-disabling of instrumentations

[trentm]

When disableInstrumentations support was added in #353 it only
half-disabled these instrumentations, briefly mentioning "continuation
patches". I believe this was about user-land callback queue handling
that should no longer be necessary after run-context and #2430 work.

In #2498 it was discussed and decided that if listed in
disableInstrumentations the agent should not touch the module at all.

Checklist

• Implement code: update from main, this is currently a bit out of date.
• Test with TAV run.
• Add CHANGELOG.asciidoc entry (an entry was added in the 3.26.0 release).

[apmmachine]

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• Reason: null

• Start Time: 2022-01-28T22:02:33.827+0000

• Duration: 30 min 27 sec

• Commit: b02ddde

Test stats 🧪

Test	Results
Failed	0
Passed	243533
Skipped	0
Total	243533

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

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• run module tests for <modules> : Run TAV tests for one or more modules, where <modules> can be either a comma separated list of modules (e.g. memcached,redis) or the string literal ALL to test all modules

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[trentm]

run module tests for mysql,pg,redis,ioredis

[trentm]

@elastic/observablt-robots Would one of you be able to look into why the run module tests for mysql,pg,redis,ioredis comment above did not do anything? https://apm-ci.elastic.co/job/apm-agent-nodejs/job/apm-agent-nodejs-mbp/job/PR-2444/ only has the original build from when this PR was opened.

[cachedout]

Would one of you be able to look into why the run module tests for mysql,pg,redis,ioredis comment above did not do anything?

Paging @elastic/observablt-robots-on-call

[v1v]

Would one of you be able to look into why the run module tests for mysql,pg,redis,ioredis comment above did not do anything?

IIUC, run module tests for mysql,pg,redis,ioredis matches ^run (module|benchmark) tests, but it's not, it should be ^run (module|benchmark) tests .*

Let me put a fix

[trentm]

run module tests for redis,mysql