Match: Refactor the unsigned SAT_ADD match pattern [NFC]

This patch would like to refactor the unsigned SAT_ADD pattern by:
* Extract type check outside.
* Extract common sub pattern.
* Re-arrange the related match pattern forms together.
* Remove unnecessary helper pattern matches.

The below test suites are passed for this patch.
* The rv64gcv fully regression test.
* The x86 bootstrap test.
* The x86 fully regression test.

gcc/ChangeLog:

	* match.pd: Refactor sorts of unsigned SAT_ADD match pattern.

Signed-off-by: Pan Li <pan2.li@intel.com>
Signed-off-by: Pan Li <pan2.li@intel.com>