planner: fix different err msg from MySQL when group by window function (#16134)

[sre-bot]

cherry-pick #16134 to release-3.0

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What problem does this PR solve?

Issue Number: close #11518

Problem Summary: When GROUP BY is followed by a number in a select stmt and this number correspond to a window function in select fields, TiDB prints a different error message from MySQL.

What is changed and how it works?

What's Changed: When dealing with ast.PositionExpr in gbyResolver's Leave() method, we check if it's a ast.WindowFuncExpr. If so, ErrWrongGroupField will occur, which is expected.

Check List

Tests

• Unit test

[sre-bot]

/run-all-tests

[eurekaka]

@time-and-fate Please help take a look at the CI failure.

[time-and-fate]

@eurekaka An error is returned by testPlanSuite.ParseOneStmt() on the new added test case. Seems like indicating a syntax error. Then I happened to find that testPlanSuite.Parser.lexer.supportWindowFunc is false. I think this might be the cause.
How can I help to fix it?

[eurekaka]

@time-and-fate you can replace ParseOneStmt with ParseSQL in the test, or move the added case to a test which uses ParseSQL

[eurekaka]

How does it succeed in master branch BTW?

[time-and-fate]

@eurekaka supportWindowFunc is switched on in SetUpSuite() in logical_plan_test.go in pr #13406
Should we also add these code here?

s.ctx.GetSessionVars().EnableWindowFunction = true
s.Parser.EnableWindowFunc(true)

[eurekaka]

@time-and-fate Yes please.

[SunRunAway]

Cherry-picked in manual, #16210