kv/client: refine region reconnect and resolve lock strategy (#1949)

[ti-chi-bot]

This is an automated cherry-pick of #1949

What problem does this PR solve?

Fix some bugs and adjust kv client strategies according to some internal test results.

What is changed and how it works?

• Fix a bug in kv client v1/v2 that some region token is not released correctly
• Decrease grpcMaxCallRecvMsgSize to 256MB (From test this doesn't affect throughtput)
• Remove un-initialized region reconnect mechanism
• Increase initialized region reconnect threshold from 15min to 60min
• Check resolve lock with last event received time, instead of the lastResolvedTs, resolve lock optimization will be in another PR

Check List

Tests

• Unit test
• Integration test

Release note

• No release note

[ti-chi-bot]

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[ti-chi-bot]

@ti-chi-bot: This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-chi-bot]

@ti-chi-bot: PR needs rebase.

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[amyangfei]

Cherry-picked in #2149