Fix deadlock issue in DeferredResult

Previously DeferredResult locked around the setting of the result
including handling up to the part of submitting a dispatch. This
can cause a deadlock if a timeout occurs at the same time since
the Tomcat timeout thread has its own locking that permits only
one thread to do timeout or dispatch processing.

The fix reduces the locking to cover only the attempt to set the
DeferredResult but not the dispatching.

Issue: SPR-10485
Reinstate removal of semicolon content

Commit 5b1165 was an attempt to leave semicolon content in the URL path
while ignoring it for request mapping purposes. However, it becomes
quite difficult to manage and semicolon content should not always be
ignored (sometimes a semicolon is used as a separator of multiple items
in a path segment, rather than for matrix variables).

This change effectively reverts back to the original approach in 3.2
where a flag on AbstractHandlerMapping can be used to have semicolon
content removed or kept. If kept, path segments with matrix variables
must be represented with a path segment.

The main difference is that by default it is removed everywhere
including the MVC namespace and Java config.

Issue: SPR-10427, SPR-10234
Make removal of jsessionid case insensitive

Issue: SPR-10398