*: make domain Reload() thread safe

[tiancaiamao]

What problem does this PR solve?

Issue Number: close #58712

Problem Summary:

What changed and how does it work?

InfoSchema is a global instance, domain.Reload() will reload the schema and update it.
This should be a thread-safe operation.

After #58466, we assume the visit pattern is one writes multiple readers.

Check List

Tests

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

  • I checked and no code files have been changed.

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

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.9855%. Comparing base (67249cb) to head (0f99e28).
Report is 11 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #58722        +/-   ##
================================================
+ Coverage   73.0858%   74.9855%   +1.8997%     
================================================
  Files          1676       1723        +47     
  Lines        463685     478976     +15291     
================================================
+ Hits         338888     359163     +20275     
+ Misses       103941      97153      -6788     
- Partials      20856      22660      +1804     

Flag	Coverage Δ
integration	48.8448% <90.9090%> (?)
unit	72.3093% <100.0000%> (+0.0290%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	52.6910% <ø> (ø)
parser	∅ <ø> (∅)
br	61.6822% <ø> (+15.9611%)	⬆️

[tiancaiamao]

/retest

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[D3Hunter]

we have a lock here, how it enter twice?

tidb/pkg/domain/domain.go

Lines 768 to 777 in 7063a6f

	func (do *Domain) Reload() error {
	failpoint.Inject("ErrorMockReloadFailed", func(val failpoint.Value) {
	if val.(bool) {
	failpoint.Return(errors.New("mock reload failed"))
	}
	})
	// Lock here for only once at the same time.
	do.m.Lock()
	defer do.m.Unlock()

[lance6716]

to avoid dead waiting, also select from domain's exit channel

Also I'm not sure about the up-to-date guarantee of Reload. can we use singleflight to merge concurrent invocation?

[tiancaiamao]

Use #58815 instead.