gcc/testsuite/gcc.dg: Fix pic test case for PE targets

gcc/testsuite/ChangeLog:

	* gcc.dg/pic-2.c: Fix expected __PIC__ value.
	* gcc.dg/pic-3.c: Ditto.
	* gcc.dg/pic-4.c: Ditto.

Signed-off-by: Jonathan Yong <10walls@gmail.com>