Prior to this commit, AntPathMatcher would not correctly combine a path
that ends with a separator with a path that starts with a separator.
For example, `/foo/` + `/bar` combined into `/foo//bar`.
Specifically, this commit:
- Removes the duplicated separator in combined paths
- Improves RequestMappingInfo's toString() representation
- Fixes Javadoc formatting in AntPathMatcher
- Polishes AntPathMatcherTests
- Polishes Javadoc in AbstractRequestCondition
Issue: SPR-12975
(cherry picked from commit a80d0e87a4)
bf423b2ca0