Revert "Improve suffix pattern check"

This reverts commit 3474afb165b6efa1a15db87c088e0fe79353000f.

Unfortunately this change is likely to cause issues for applications
that use regular expressions in a URI variable. I think we will have
to leave at: if there are any dots in the last segment of the
request path, regardless of whether they're in a URI var or not,
the suffix pattern match is off.

Issue: SPR-11532