prerender: Verify that a mismatched url will not activate prerender with target_hint=_blank

This CL adds a test to improve the code coverage for this follow section
by verifying a different url will not activate a mismatched prerender
with target_hint `_blank` and the navigation will not cancel the
prerender.
https://source.chromium.org/chromium/chromium/src/+/1d060dbaebc59f11ea620ecbb3edc656d0222d88:content/browser/preloading/prerender/prerender_new_tab_handle.cc;l=122;bpv=1;bpt=0

Bug: 40234240
Change-Id: I9273bdfe99d70be36b20f864930fdaa9acd8310a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6535055
Commit-Queue: Huanpo Lin <robertlin@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1459250}