sql/parser: only retain scanned SQL comments when necessary

[mgartner]

In #86968 the scanner gained the ability to retain comments in scanned
SQL strings, and this was an always-on feature. However, the comments
are only used when populating the crdb_internal.cluster_queries table,
see sql.formatActiveQuery. Now, comments are only retained when the
parser is used from this function, reducing allocations for all other
cases.

Fixes #127713

Release note: None

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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[cockroach-teamcity]

This change is 

[DrewKimball]

Nice! Just a nit.

Reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @mgartner and @mw5h)

---

pkg/sql/parser/parse.go line 151 at r1 (raw file):

const (
	retainComments  commentsMode = true
	disgardComments commentsMode = false

[nit] disgard -> discard here and elsewhere.

[mgartner]

TFTR!

bors r+

Reviewable status: complete! 0 of 0 LGTMs obtained (and 1 stale) (waiting on @DrewKimball and @mw5h)

---

pkg/sql/parser/parse.go line 151 at r1 (raw file):

Previously, DrewKimball (Drew Kimball) wrote…

[nit] disgard -> discard here and elsewhere.

Good catch. Fixed!

[craig]

Build failed (retrying...):

• unit_tests

[craig]

Build succeeded:

• linux_amd64_fips_build
• lint
• linux_amd64_build
• acceptance
• macos_amd64_build
• local_roachtest
• windows_build
• examples_orms
• linux_arm64_build
• local_roachtest_fips
• macos_arm64_build
• check_generated_code
• docker_image_amd64
• unit_tests

[rafiss]

Nice fix! Should this get backported?

[rafiss]

Nevermind, I see that #127711 was backported, and I think that's the only one that should be.