[Improvement](schema scan) Use async scanner for schema scanners (#38…

[Gabriel39]

…403)

Proposed changes

Issue Number: close #xxx

[doris-robot]

Thank you for your contribution to Apache Doris.
Don't know what should be done next? See How to process your PR

Since 2024-03-18, the Document has been moved to doris-website.
See Doris Document.

[Gabriel39]

run buildall

[github-actions]

clang-tidy made some suggestions

[github-actions]

warning: pointer parameter 'eos' can be pointer to const [readability-non-const-parameter]

be/src/exec/schema_scanner.h:101:

- Status get_next_block(RuntimeState* state, vectorized::Block* block, bool* eos);+ Status get_next_block(RuntimeState* state, vectorized::Block* block, const bool* eos);

Suggested change

	Status SchemaScanner::get_next_block(RuntimeState* state, vectorized::Block* block, bool* eos) {
	Status SchemaScanner::get_next_block(RuntimeState* state, vectorized::Block* block, constbool* eos) {

[doris-robot]

TeamCity be ut coverage result:
Function Coverage: 36.43% (9254/25405)
Line Coverage: 27.98% (75673/270440)
Region Coverage: 26.80% (38901/145177)
Branch Coverage: 23.52% (19735/83912)
Coverage Report: http://coverage.selectdb-in.cc/coverage/6e1f5dcd37fcc0f6ee47a1b0b03d63040be4fbc7_6e1f5dcd37fcc0f6ee47a1b0b03d63040be4fbc7/report/index.html