Match: Remove dup match pattern for signed_integer_sat_sub [PR117141]

Match: Remove dup match pattern for signed_integer_sat_sub [PR117141]

This patch would like to fix the warning as below:

/home/slyfox/dev/git/gcc/gcc/match.pd:3424:3 warning: duplicate pattern
 (cond^ (ne (imagpart (IFN_SUB_OVERFLOW:c@2 @0 @1)) integer_zerop)
  ^
/home/slyfox/dev/git/gcc/gcc/match.pd:3397:3 warning: previous pattern
defined here
 (cond^ (ne (imagpart (IFN_SUB_OVERFLOW@2 @0 @1)) integer_zerop)

The second has a optional nop_convert which allows for the first one,
thus remove the dup one.

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

	PR middle-end/117141

gcc/ChangeLog:

	* match.pd: Remove the dup pattern for signed SAT_SUB.

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