Prior to this commit, patterns like `"/path/**/other"` would be treated
as `"/path/*/other"` (single wildcard, i.e. matching zero to many chars
within a path segment). This will not match multiple segments, as
expected by `AntPathMatcher` users or by `PathPatternParser` users when
in patterns like `"/resource/**"`.
This commit now rejects patterns like `"/path/**/other"` as invalid.
This behavior was previously warned against since gh-24958.
Closes gh-24952
e4cb25f365