[backport -> release/3.6.x] fix(request-debugging): add missing router section of the timing output

[team-gateway-bot]

Automated backport to release/3.6.x, triggered by a label in #12234.

Original description

## Blocked by #12580

Summary

We have already added calls of the hook to measure the time consumed by the router.

kong/kong/runloop/handler.lua

Lines 1152 to 1162 in f7e6eee

	if has_timing then
	req_dyn_hook_run_hooks(ctx, "timing", "before:router")
	end
	-- routing request
	local router = get_updated_router()
	local match_t = router:exec(ctx)
	if has_timing then
	req_dyn_hook_run_hooks(ctx, "timing", "after:router")
	end

But forgot to setup the hook function, this PR setups the hook function for the router.

And also fix some tests that might cause flakiness.

Checklist

• The Pull Request has tests
• A changelog file has been created under changelog/unreleased/kong or skip-changelog label added on PR if changelog is unnecessary. README.md
• [N/A] There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Issue reference

KAG-3438

[team-gateway-bot]

Cherry-pick failed for release/3.6.x: couldn't find remote ref release/3.6.x.
Please ensure that this Github repo has a branch named release/3.6.x.

[team-gateway-bot]

Cherry-pick failed for release/3.6.x, because it was unable to create a new branch.

Please cherry-pick the changes locally.

git remote add upstream https://github.com/kong/kong-ee
git fetch upstream release/3.6.x
git worktree add -d .worktree/cherry-pick-12649-to-release/3.6.x-to-upstream upstream/release/3.6.x
cd .worktree/cherry-pick-12649-to-release/3.6.x-to-upstream
git checkout -b cherry-pick-12649-to-release/3.6.x-to-upstream
ancref=$(git merge-base 9005436af615fd519c89eb404fec46c1799b1596 9bc2faa1ffea93f97459f277fa33626c0c5d9010)
git cherry-pick -x $ancref..9bc2faa1ffea93f97459f277fa33626c0c5d9010