[FLINK-40239][runtime] Support additional Flink SQL regular expression functions in YAML Transform

[haruki-830]

Summary

This commit adds support for five additional Flink SQL regular expression functions in YAML Transform: REGEXP_EXTRACT, REGEXP_EXTRACT_ALL, REGEXP_COUNT, REGEXP_INSTR, and REGEXP_SUBSTR.

The functions use Java regular expression syntax and align with Flink SQL semantics for NULL values, invalid patterns, capture groups, and no-match cases.

Key Changes

1. Additional Regular Expression Functions

• Added implementations for the five missing regular expression functions.
• Supports capture group indexes in REGEXP_EXTRACT and REGEXP_EXTRACT_ALL.
• Uses the expected no-match behavior:
  • REGEXP_EXTRACT and REGEXP_SUBSTR return NULL.
  • REGEXP_EXTRACT_ALL returns an empty array.
  • REGEXP_COUNT and REGEXP_INSTR return 0.
• Invalid regular expressions and invalid capture group indexes return NULL.

2. YAML Transform Integration

• Registered the new functions in the Transform SQL operator table.
• Added return type inference for ARRAY<STRING> from REGEXP_EXTRACT_ALL.
• Verified that REGEXP_EXTRACT_ALL works correctly in YAML Transform projections.
• Existing REGEXP_REPLACE behavior remains unchanged.

3. Test Coverage

• Added unit tests covering NULL arguments, invalid patterns, no matches, capture groups, and invalid group indexes.
• Added parser tests for function registration and expression translation.
• Added projection tests covering the runtime conversion of REGEXP_EXTRACT_ALL results.

4. Documentation

• Documented the five new functions in both English and Chinese Transform documentation.

JIRA Reference

https://issues.apache.org/jira/browse/FLINK-40239

[haruki-830]

@lvyanquan @yuxiqian PTAL, thanks!