[AArch64][testsuite][committed] Fix gcc.target/aarch64/combine_bfxil.c for -mabi...

[AArch64][testsuite][committed] Fix gcc.target/aarch64/combine_bfxil.c for -mabi=ilp32

As described in https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00963.html this test generates UXTW instructions with -mabi=ilp32
because the foo* functions take pointers and store results into them. In ILP32 the callee clears the top bits with a UXTW.
This trips the scan-assembler-not UXTW test that checks that the zero_extend form of the BFXIL pattern is used, which it is.

This patch avoids this problem by not passing pointers to the results, but instead using global variables for which the foo* functions
will synthesise the address using ADRP, avoiding the UXTW instructions.

With this patch the test PASSes fully with -mabi=ilp32 and still PASSes on LP64.

	* gcc.target/aarch64/combine_bfxil.c: Avoid passing pointers to
	functions.

From-SVN: r264389