gcc/testsuite: adjust tree-ssa/forwprop-43.c

Introduced in r16-5042-g470411f44f51d9, this testcase fails on
AdvSIMD-less AArch32 configurations, likely as well as on other targets
without vector support; thus, require it via dg-require-effective-target.
Since this testcase includes stdint.h, require that as well.

Regtested on arm-gnueabihf with
RUNTESTFLAGS=--target_board=unix/-mfpu=vfpv3-d16/-march=armv7-a.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/forwprop-43.c: Adjust.

gcc/testsuite/gcc.dg/tree-ssa/forwprop-43.c

@@ -1,5 +1,7 @@
 /* { dg-do compile } */
 /* { dg-options "-O2 -fdump-tree-forwprop1" } */
+/* { dg-require-effective-target stdint_types } */
+/* { dg-require-effective-target vect_int } */
 /* { dg-additional-options "-fgimple" } */
 
 #include <stdint.h>