[AArch64][committed] Fix gcc.target/aarch64/combine_bfi_1.c

[AArch64][committed] Fix gcc.target/aarch64/combine_bfi_1.c

This test started failing because some of the functions in the combine dump that it scans uses a different pattern to match the same instruction: insv_regsi rather than aarch64_bfi.
The code generation is still the same.
The patch changes the scan to look for the actual instruction we want in the assembly.

This fixes the test.
Committing to trunk as obvious.

     * gcc.target/aarch64/combine_bfi_1.c: Scan for bfi instruction
     rather than pattern name in combine dump.

From-SVN: r264323