restore: Fix system tables are filtered bug (#1207)

[ti-chi-bot]

This is an automated cherry-pick of #1207

What problem does this PR solve?

Fix issue #1197 and #1201
When user only want to restore the system table, i.e. -f "mysql*.*", because the system database was rename to a temporary name, that name will be filtered causing no system table is restored

What is changed and how it works?

When filter restore databases and tables, revert the temporary name to its original name

Check List

Tests

• Integration test

Code changes

• Has exported function/method change

Related changes

• Need to cherry-pick to the release branch

Release note

• No Release Note

[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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[kennytm]

[2021-06-16T03:16:39.528Z] + run_sql 'SELECT count(*) from mysql.bar;'

[2021-06-16T03:16:39.528Z] + grep 11

[2021-06-16T03:16:39.528Z] ERROR 1146 (42S02) at line 1: Table 'mysql.bar' doesn't exist

🤔

[ZipFast]

@kennytm
[2021-06-16T03:16:38.440Z] [2021/06/16 11:16:38.264 +08:00] [DEBUG] [systable_restore.go:46] ["system database filtered out"] [database=mysql]
It seems that the temporary system db is filtered out.

[ZipFast]

/run-all-tests

[ZipFast]

@YuJuncen

	if !f.MatchSchema(temporaryDB.O) {
		log.Debug("system database filtered out", zap.String("database", sysDB))
		return
	}

It seems the temporaryDB.O will be filtered out, and should be replaced with sysDB?

[ZipFast]

/run-all-tests

[ZipFast]

/build

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• 3pointer
• kennytm

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[3pointer]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 21d5737