ext/uri: Reorganises legacy tests

[NickSdot]

WIP

Ref: #23271 (review) @kocsismate
Depends on: #23271

Coverage

Coverage: ext/uri

Base: 5332ab0c291361abe3d12db21dd55e5dc7baa829 upstream/master
Tree: 4c3ac49bea7d49c131c8f0145ccdf444f03932b9 hardening/ext-uri-reorg

+--------+-------+---------+--------------------+------------------+--------+---------+
|        | Tests | Sources |              Lines |         Branches |   Time |  Memory |
+--------+-------+---------+--------------------+------------------+--------+---------+
| Base   |   374 |       7 | 1697/1934 (87.75%) | 589/968 (60.85%) |  5.10s | 27.8 MB |
| Tree   |   382 |       7 | 1697/1934 (87.75%) | 589/968 (60.85%) |  5.00s | 28.0 MB |
| Change |    +8 |       0 |   +0 / -0 (+0.00%) | +0 / -0 (+0.00%) | -0.10s | +0.1 MB |
+--------+-------+---------+--------------------+------------------+--------+---------+