REGTESTS: uri_normalizer: test a normalizer used with a condition

REGTESTS: uri_normalizer: test a normalizer used with a condition

The existing tests always use the normalizers unconditionally, so the
selection of the normalizer when a condition directly follows a
normalizer whose sub-option is omitted was not covered.

The request uses both a percent sequence and duplicate slashes so that
the expected result differs depending on which normalizer is picked:
percent-decode-unreserved leaves the duplicate slashes alone, while
path-merge-slashes, which was wrongly selected before the previous
commit, would merge them and leave the percent sequence encoded.