General ExcelViewTests code update

Issue: SPR-11334
Polishing
Deprecated AbstractJExcelView since JExcelAPI is an abandoned project

JXL had no release since 2009, and has some serious bugs remaining: e.g. JXL on Unix cannot read template files created on Windows, using the 'latest' JXL 2.6.12 release.
Consider wildcard type without bounds as eligible for fallback match too

Issue: SPR-11250
Upgrade to jexcelapi 2.6.12 and fix test failures

Upgrade to the latest release of jexcelapi and work-around the
ArrayIndexOutOfBounds test exception on *nix machines.

Issue: SPR-11334
Allow HttpHeaders return values for @MVC methods

Allow HttpHeader instances to be returned directly from MVC controller
methods managed by HandlerMethodReturnValueHandler rather than needing
to be wrapped in a ResponseEntity.

Issue: SPR-11129
Polish

Issue: SPR-11129
Revert previous impl for SPR-10163

This reverts commit 96b418cc8ae537e985cfe67b80cd866d03c8060f,
"Make RequestMappingHandlerMapping xml config easier".

This implementation makes the mvc:annotation namespace less readable,
and future configuration items would add even more to this namespace.

Issue: SPR-10163
Make RequestMappingHandlerMapping xml config easier

Prior to this commit, it was necessary to override
the HandlerMapping definition to change properties
like useSuffixPatternMatch, useSuffixPatternMatch...
Also, one couldn't set custom pathmatcher/pathhelper
on RequestMappingHandlerMapping via XML configuration.

This commits adds a new "mvc:annotation-driven"
subelement called "mvc:path-matching" for the tag
that allows to configure such properties:
* suffix-pattern
* trailing-slash
* registered-suffixes-only
* path-matcher
* path-helper

Note: this is a new take on this issue, since
96b418cc has been reverted by e2b99c3.

Issue: SPR-10163