avx2-gather-1.c: Add -march.
* gcc.target/i386/avx2-gather-1.c: Add -march.
* gcc.target/i386/avx2-gather-2.c: Add -march.
* gcc.target/i386/avx2-gather-3.c: Add -march.
* gcc.target/i386/avx2-gather-4.c: Add -march.
* gcc.target/i386/avx2-gather-5.c: Add -march.
* gcc.target/i386/avx2-gather-6.c: Add -march.
* gcc.target/i386/avx512f-gather-1.c: Add -march.
* gcc.target/i386/avx512f-gather-2.c: Add -march.
* gcc.target/i386/avx512f-gather-3.c: Add -march.
* gcc.target/i386/avx512f-gather-4.c: Add -march.
* gcc.target/i386/avx512f-gather-5.c: Add -march.
* gcc.target/i386/avx512f-i32gatherd512-1.c: Add -march.
* gcc.target/i386/avx512f-i32gatherd512-2.c: Add -march.
* gcc.target/i386/avx512f-i32gatherpd512-1.c: Add -march.
* gcc.target/i386/avx512f-i32gatherpd512-2.c: Add -march.
* gcc.target/i386/avx512f-i32gatherps512-1.c: Add -march.
From-SVN: r256423