test: test bottom-up merge sort in URLSearchParams

Following up for this commit: https://github.com/nodejs/node/commit/02d1e32fe351078ae7d7e2e0dfb7fe3fa5f75986 to increase the reduced coverage. The bottom-up iterative stable merge sort is called only when the length of provided value is larger than 100. Added a test for it.

This increases the coverage of internal/url.js,

• https://coverage.nodejs.org/coverage-e4e7cd5bd202084b/root/internal/url.js.html

and the following lines will be covered.

• https://github.com/nodejs/node/blob/e4e7cd5bd202084b4e6af401a634ca151e82d956/lib/internal/url.js#L701-L727
• https://github.com/nodejs/node/blob/e4e7cd5bd202084b4e6af401a634ca151e82d956/lib/internal/url.js#L886-L900

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

test