Fix a few vect gimple testcases for LLP64 targets (e.g. mingw) [PR113548]

Fix a few vect gimple testcases for LLP64 targets (e.g. mingw) [PR113548]

This fixes of the vect testcases which uses the gimple FE for LLP64 targets.
The testcases use directly `unsigned long` for the addition to pointers
when they should be using `__SIZETYPE__`. This changes to use that instead.

gcc/testsuite/ChangeLog:

	PR testsuite/113548
	* gcc.dg/vect/slp-reduc-10a.c: Use `__SIZETYPE__` instead of `unsigned long`.
	* gcc.dg/vect/slp-reduc-10b.c: Likewise.
	* gcc.dg/vect/slp-reduc-10c.c: Likewise.
	* gcc.dg/vect/slp-reduc-10d.c: Likewise.
	* gcc.dg/vect/slp-reduc-10e.c: Likewise.
	* gcc.dg/vect/vect-cond-arith-2.c: Likewise.
	* gcc.dg/vect/vect-ifcvt-19.c: Likewise.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>