urlmon/tests: Remove unused strings (Clang)

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://testbot.winehq.org/JobDetails.pl?Key=10595

Your paranoid android.


=== w2008s64 (32 bit url) ===
url.c:1478: Test failed: progress 2: hres = 1, expected 0
url.c:1668: Test failed: unexpected call OnProgress_FINDINGRESOURCE
url.c:1478: Test failed: progress 1: hres = 1, expected 0
url.c:1680: Test failed: unexpected call OnProgress_CONNECTING
url.c:1478: Test failed: progress 2: hres = 1, expected 0
url.c:1701: Test failed: unexpected call OnProgress_SENDINGREQUEST