Fix accepting bind variables in time related function calls.

[GuptaManan100]

Description

As part of the PR #12742 we changed curtime function expressions to only accept literal values instead of taking in bind variables. This however caused the problem described in #14740 where-in, the vtgates from v16 are still normalizing the query and sending bind-variables, but the v17 vttablets aren't accepting them.

This PR addresses this issue, by making v17 vttablets to continue to parse the bind-variables and it also fixes the normalizer to continue to not normalize the curtime function expressions.

Tests for all the changes have been added. Moreover, I have added running the misc package of vtgate queries in upgrade-downgrade tests.

Related Issue(s)

• Fixes Bug Report: Insert query cannot accept now(3) as timestamp value (Major regression from v17.0.4 and above) during upgradation #14740

Checklist

• "Backport to:" labels have been added if this change should be back-ported
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on the CI
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

Review Checklist

Hello reviewers! 👋 Please follow this checklist when reviewing this Pull Request.

General

• Ensure that the Pull Request has a descriptive title.
• Ensure there is a link to an issue (except for internal cleanup and flaky test fixes), new features should have an RFC that documents use cases and test cases.

Tests

• Bug fixes should have at least one unit or end-to-end test, enhancement and new features should have a sufficient number of tests.

Documentation

• Apply the release notes (needs details) label if users need to know about this change.
• New features should be documented.
• There should be some code comments as to why things are implemented the way they are.
• There should be a comment at the top of each new or modified test to explain what the test does.

New flags

• Is this flag really necessary?
• Flag names must be clear and intuitive, use dashes (-), and have a clear help text.

If a workflow is added or modified:

• Each item in Jobs should be named in order to mark it as required.
• If the workflow needs to be marked as required, the maintainer team must be notified.

Backward compatibility

• Protobuf changes should be wire-compatible.
• Changes to _vt tables and RPCs need to be backward compatible.
• RPC changes should be compatible with vitess-operator
• If a flag is removed, then it should also be removed from vitess-operator and arewefastyet, if used there.
• vtctl command output order should be stable and awk-able.

[harshit-gangal]

Looks like a genuine failure here due to changes

2023-12-13T07:59:56.7049644Z === RUN   TestSetUDV/17-set_@foo_=_now(),_@bar_=_now(),_@dd_=_date('2020-10-20'),_@tt_=_time('10:15')
2023-12-13T07:59:56.7050937Z     udv_test.go:112: 
2023-12-13T07:59:56.7052334Z         	Error Trace:	/home/runner/work/vitess/vitess/go/test/endtoend/vtgate/reservedconn/utils.go:150
2023-12-13T07:59:56.7054893Z         	            				/home/runner/work/vitess/vitess/go/test/endtoend/vtgate/reservedconn/udv_test.go:112
2023-12-13T07:59:56.7056196Z         	Error:      	Received unexpected error:
2023-12-13T07:59:56.7059396Z         	            	Bind variables not supported for CurTimeFuncExpr (errno 1105) (sqlstate HY000) during query: set @foo = now(), @bar = now(), @dd = date('2020-10-20'), @tt = time('10:15')
2023-12-13T07:59:56.7061843Z         	Test:       	TestSetUDV/17-set_@foo_=_now(),_@bar_=_now(),_@dd_=_date('2020-10-20'),_@tt_=_time('10:15')
2023-12-13T07:59:56.7063698Z         	Messages:   	for query: set @foo = now(), @bar = now(), @dd = date('2020-10-20'), @tt = time('10:15')
2023-12-13T07:59:56.7064835Z === RUN   TestSetUDV/18-select_@foo_=_@bar,_@dd,_@tt
2023-12-13T07:59:56.7065617Z     udv_test.go:118:   string(
2023-12-13T07:59:56.7066535Z         - 	`[[INT64(1) DATE("2020-10-20") TIME("10:15:00")]]`,
2023-12-13T07:59:56.7067292Z         + 	"[[INT64(0) NULL NULL]]",
2023-12-13T07:59:56.7067855Z           )
2023-12-13T07:59:56.7068217Z         
2023-12-13T07:59:56.7068778Z         for query: select @foo = @bar, @dd, @tt
2023-12-13T07:59:56.7069468Z --- FAIL: TestSetUDV (0.03s)

[GuptaManan100]

Okay, yes. I found the failure and fixed it 👍