test: support multiple make targets in single matrix entry (apache#766)

Enhances test execution framework to support running multiple make targets
within a single matrix entry while maintaining independent result tracking
and reporting. This allows grouping related tests (e.g., extensions)
together while preserving detailed test results for each configuration.

Key changes:
- Modifies matrix configuration to use make_configs array instead of
  separate make_target/make_directory fields
- Enhances test execution to process each make configuration independently
- Updates results parsing to maintain separate result files per
  configuration
- Modifies test summary generation to report each configuration's results
  independently
- Adds improved error handling and status tracking per configuration
- Maintains backward compatibility with existing single-target test
  configurations

Test Enhancements:
- Move singlenode tests into its own test group
- Introduce ic_contrib test group
  - contrib/auto_explain:installcheck
  - contrib/citext:installcheck
  - contrib/btree_gin:installcheck
  - contrib/file_fdw:installcheck
  - contrib/formatter_fixedwidth:installcheck
  - contrib/extprotocol:installcheck
  - contrib/dblink:installcheck
  - contrib/pg_trgm:installcheck
  - contrib/indexscan:installcheck
  - contrib/hstore:installcheck
  - contrib/pgcrypto:installcheck
  - contrib/tablefunc:installcheck
  - contrib/passwordcheck:installcheck
- Introduce ic_gpcontrib test group
  - gpcontrib/orafce:installcheck
  - gpcontrib/pxf_fdw:installcheck
  - gpcontrib/zstd:installcheck
  - gpcontrib/gp_sparse_vector:installcheck

Example usage:
```yaml
- test: ic-extensions
  make_configs:
    - "src/interfaces/gppc:installcheck"
    - "contrib/citext:installcheck"
    - "contrib/btree_gin:installcheck"
```

Test Environment
- Pin workflow image to ubuntu-22.04

Author: edespino