enhance: Convert unincode to ascii to improving expression parsing efficiency

[xiaocai2333]

issue: #36672

[mergify]

@xiaocai2333 E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.26%. Comparing base (1f47d55) to head (67281c9).
Report is 9 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #36675      +/-   ##
==========================================
- Coverage   73.29%   73.26%   -0.04%     
==========================================
  Files        1286     1286              
  Lines      152093   152070      -23     
==========================================
- Hits       111484   111417      -67     
- Misses      35575    35609      +34     
- Partials     5034     5044      +10     

Files with missing lines	Coverage Δ
internal/parser/planparserv2/parser_visitor.go	89.34% <100.00%> (ø)
internal/parser/planparserv2/plan_parser_v2.go	89.09% <100.00%> (+1.67%)	⬆️
internal/parser/planparserv2/utils.go	92.60% <100.00%> (+0.31%)	⬆️

... and 41 files with indirect coverage changes

[xiaofan-luan]

/lgtm
/approve

[xiaofan-luan]

/lgtm
/approve

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: xiaocai2333, xiaofan-luan

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [xiaofan-luan]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment