[Committed] Fix tree-optimization/103152: Still one more -signed1bit issue

[Committed] Fix tree-optimization/103152: Still one more -signed1bit issue

When I fixed PR 102622, I accidently left behind a TYPE_PRECISION
check which I had there for checking before hand.  This check
is not needed as the code will handle it correctly anyways.

Committed as obvious after a bootstrap/test on x86_64-linux-gnu.

	PR tree-optimization/10352

gcc/ChangeLog:

	* match.pd: Remove check of TYPE_PRECISION for
	the a?0:pow2 case.

gcc/testsuite/ChangeLog:

	* gcc.c-torture/execute/pr10352-1.c: New test.