Previously `HandlerMapping` implementation were heavily relying on
`String` path patterns, `PathMatcher` implementations and dedicated maps
for matching incoming request URL to an actual request handler.
This commit adds the `PathPatternRegistry` that holds `PathPattern`
instances and the associated request handler — matching results are then
shared as `PathMatchResult` instances. `AbstractUrlHandlerMapping` will
use this registry directly, but other components dealing with request
matching (like `PatternsRequestCondition`) will directly use ordered
`PathPattern` collections since ordering is important there.
This opens the door for faster request matching and simplifies the
design of this part.
Issue: SPR-15608
233c15b80e