test(psl): add missing test cases for multiple generators with the same provider name

[jkomyno]

This PR adds missing test cases for multiple generators with the same provider name

[github-actions]

WASM Query Engine file Size

Engine	This PR	Base branch	Diff
Postgres	2.184MiB	2.184MiB	0.000B
Postgres (gzip)	874.500KiB	874.500KiB	0.000B
Mysql	2.149MiB	2.149MiB	0.000B
Mysql (gzip)	859.683KiB	859.683KiB	0.000B
Sqlite	2.059MiB	2.059MiB	0.000B
Sqlite (gzip)	825.420KiB	825.421KiB	-1.000B
SQL Server	2.115MiB	2.115MiB	0.000B
SQL Server (gzip)	849.285KiB	849.285KiB	0.000B
CockroachDB	2.206MiB	2.206MiB	0.000B
CockroachDB (gzip)	884.034KiB	884.034KiB	0.000B

[codspeed-hq]

CodSpeed Performance Report

Merging #5505 will not alter performance

_{Comparing feat/psl-multi-client-tests (6ef83a2) with main (f67607f)}

Summary

✅ 11 untouched benchmarks