Consider the following two URLs:

jar:file:/test.jar!/BOOT-INF/classes!/foo.txt
jar:file:/test.jar!/BOOT-INF/classes/foo.txt

They both reference the same foo.txt file in the BOOT-INF/classes
directory of test.jar, however the first URL does so via the
nested BOOT-INF/classes archive. Previously, this difference in the
URLs would lead to PathMatchingResourcePatternResolver returning two
resources for foo.txt when asked to find all resources matching the
pattern classpath*:/**/*.txt.

This commit updates our Handler that is used for jar: URLs to consider
the two URLs above to be equivalent such that url1 is equal to url2
and the two urls will produce the same hash code.

Closes gh-7449