planner: refactor the code for ExecutePreparedStmt

[Reminiscent]

What problem does this PR solve?

Issue Number: close #32371

Problem Summary:
Remove the wrong handle logic in the ExecutePreparedStmt function. We don't need the fast path for the point get plan. We treat it as normal.

What is changed and how it works?

Remove the wrong handle logic in the ExecutePreparedStmt function.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

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[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/700b7ff06d3ba1a35d012433ea83617859fc477a

[Reminiscent]

/run-build-arm64 comment=true

[Reminiscent]

/run-build-arm64 comment=true

[purelind]

/run-build-arm64 comment=true

[sre-bot]

download tidb binary(linux arm64) at http://fileserver.pingcap.net/download/builds/pingcap/test/tidb/700b7ff06d3ba1a35d012433ea83617859fc477a/centos7/tidb-linux-arm64.tar.gz

[ti-chi-bot]

@Reminiscent: PR needs rebase.

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