support go time package format gc time (#996)

[lichunzhu]

cherry-pick #996 to release-4.0

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What problem does this PR solve?

resolve #994

What is changed and how it works?

Support gc time for "8m", "7h". If no unit is specified, gc duration will use day as unit as before.

It should be noticed that the max time duration unit that supported in golang is hour "h".
golang/go#11473
golang/go#17767

Check List

Tests

• Unit test
• Integration test

Code changes

• Has exported function/method change
• Has exported variable/fields change

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation
• Need to be included in the release note

Release note

• support go time duration format for pump GC configuration

[lichunzhu]

/run-all-tests

[lichunzhu]

/run-all-tests

[july2993]

for 4.0 I will merge master directly for no diverse