Update the type of control.base after changed

Update the type of control.base after changed

This patch correct the type of niter->control.base, when it is updated
as a PLUS expr.
During build PLUS expr, the result type should align with the type of
the operands.

	PR tree-optimization/102087

gcc/ChangeLog:

	* tree-ssa-loop-niter.cc (number_of_iterations_until_wrap):
	Correct PLUS result type.

gcc/testsuite/ChangeLog:

	* gcc.dg/pr102087_1.c: New test.