…ith no explicit slash (nicolas-grekas)

This PR was merged into the 4.1 branch.

Discussion
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[Routing] dont redirect routes with greedy trailing vars with no explicit slash

| Q             | A
| ------------- | ---
| Branch?       | 4.1
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #29673 #29734 #29575
| License       | MIT
| Doc PR        | -

From the linked issue:

> The current logic is the following:
> - when a route is declared with a trailing slash, the trimmed-slash url is redirected to the one with the slash
> - when a route is declared with *no* trailing slash, the slashed url is redirected to the trimmed-slash one
>
> That includes routes with slash-greedy requirements: when the same greedy requirement matches both the slashed and the trimmed-slash URLs, only one of them is considered the canonical one and a redirection happens.
>
> We could fine tune this logic and make an exception when a trailing slash-greedy requirement is declared with no explicit trailing slash after it. (ie disable any redirections for `/foo/{.*}` but keep it for `/foo/{.*}/`. That would mean `/foo/bar` and `/foo/bar/` wouldn't trigger the redirection for route `/foo/{.*}`, breaking the "not-semantics" property of trailing slashes for catch-all routes. Which might be legit afterall.

This PR implements this fine tuning, as that's the most BC behavior (and thus the correct one).
See #30012 for `testGreedyTrailingRequirement` in action on 3.4 as a proof.

Commits
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2bb8890 [Routing] dont redirect routes with greedy trailing vars with no explicit slash