expression: bug fix for vectorized casting real as ... (#19485)

[ti-srebot]

cherry-pick #19485 to release-4.0

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What problem does this PR solve?

Issue Number: close #17809

Problem Summary:

Casting from column value 0.0 of real type to datetime type produces wrong result NULL.

CREATE TABLE t0(c0 DOUBLE);
INSERT INTO t0(c0) VALUES (0);
SELECT CAST(t0.c0 AS DATETIME) FROM t0; -- expected: {0000-00-00 00:00:00}, actual: {NULL}

But casting from constant produces the expected result 0000-00-00 00:00:00.

SELECT CAST(0.0 AS DATETIME) FROM t0; -- {0000-00-00 00:00:00}

What is changed and how it works?

What's Changed:

• builtinCasrRealAsTimeSig.vecEvalTime will treat real value 0.0 as a special case, and assign ZeroTime to the result.

How it Works:

• the non-vectorized evalTime has this special case but vecEvalTime does not.
• add this special case to vecEvalTime

Related changes

Check List

Tests

• Unit test

Release note

• fix incorrect result of vectorized casting real as time

[ti-srebot]

/run-all-tests

[zz-jason]

LGTM

[lysu]

need merge with tikv/tikv#8562 to keep CI can pass

[lysu]

/run-integration-copr-test tikv=pr/8562

[lzmhhh123]

LGTM

[lzmhhh123]

It should merge with tikv/tikv#8562 together.

[zz-jason]

LGTM

[lysu]

@zz-jason tikv/tikv#8562 has all-test-pass please help merge if free (no privilege - -)