planner, expression: support builtin function NAME_CONST

[spongedu]

What problem does this PR solve?

Support builtin function NAME_CONST, part as issue #8439

What is changed and how it works?

1. implement NAME_CONST in expression/builtin_miscellaneous.go.
2. rewrite the result column name, as is described in doc: When used to produce a result set column, NAME_CONST() causes the column to have the given name .
3. the return value of NAME_CONST is actually a const, so I add an extra constant-folding rule for it.
4. add related tests.

Check List

Tests

• Unit test

Code changes

Side effects

Related changes

[codecov-io]

Codecov Report

Merging #9261 into master will decrease coverage by 0.01%.
The diff coverage is 41.34%.

@@            Coverage Diff             @@
##           master    #9261      +/-   ##
==========================================
- Coverage   67.14%   67.13%   -0.02%     
==========================================
  Files         372      372              
  Lines       77656    77747      +91     
==========================================
+ Hits        52146    52193      +47     
- Misses      20844    20886      +42     
- Partials     4666     4668       +2

Impacted Files	Coverage Δ
planner/core/preprocess.go	86.63% <10%> (-2.03%)	⬇️
planner/core/logical_plan_builder.go	74.14% <37.5%> (-0.41%)	⬇️
expression/builtin_miscellaneous.go	64.73% <47.14%> (-2.64%)	⬇️
expression/schema.go	93.75% <0%> (-0.79%)	⬇️
util/filesort/filesort.go	76.48% <0%> (+0.94%)	⬆️
store/tikv/lock_resolver.go	42.65% <0%> (+0.94%)	⬆️
ddl/delete_range.go	75.13% <0%> (+1.58%)	⬆️
ddl/session_pool.go	93.1% <0%> (+10.34%)	⬆️

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[zz-jason]

LGTM

[spongedu]

@eurekaka PTAL

[eurekaka]

LGTM

[eurekaka]

/run-all-tests

[spongedu]

@zz-jason @qw4990 PTAL :)

[zz-jason]

/run-common-test
/run-integration-common-test