executor,planner: support show create view

[AndrewDi]

What problem does this PR solve?

As part of view feature, add SHOW CREATE VIEW grammar support.

What is changed and how it works?

ref proposal Proposal: Implement View

Check List

Tests

• Unit test

[AndrewDi]

/run-all-tests

[AndrewDi]

@XuHuaiyu @zz-jason @crazycs520 PTAL

[codecov-io]

Codecov Report

Merging #9309 into master will increase coverage by <.01%.
The diff coverage is 41.66%.

@@            Coverage Diff             @@
##           master    #9309      +/-   ##
==========================================
+ Coverage   67.13%   67.13%   +<.01%     
==========================================
  Files         372      372              
  Lines       77747    77768      +21     
==========================================
+ Hits        52192    52208      +16     
- Misses      20887    20890       +3     
- Partials     4668     4670       +2

Impacted Files	Coverage Δ
ddl/ddl.go	89.53% <ø> (ø)	⬆️
planner/core/planbuilder.go	49.39% <0%> (-0.21%)	⬇️
ddl/ddl_api.go	74.76% <0%> (ø)	⬆️
executor/errors.go	100% <100%> (ø)	⬆️
executor/show.go	43.87% <60%> (+0.36%)	⬆️
executor/join.go	78.38% <0%> (+0.52%)	⬆️
store/tikv/lock_resolver.go	42.65% <0%> (+0.94%)	⬆️
infoschema/infoschema.go	77.63% <0%> (+1.31%)	⬆️

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[winkyao]

LGTM

[zz-jason]

LGTM

[zz-jason]

/run-all-tests

[AndrewDi]

@zz-jason Does common-test has broken?

[zz-jason]

@zz-jason Does common-test has broken?

oops, let me take a look

[zz-jason]

/run-common-test

[zz-jason]

@AndrewDi The CI is broken by #9331. We'll try to fix it as soon as possible.

[zz-jason]

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