[ARM] Fix selection of effective target for cmse tests

[ARM] Fix selection of effective target for cmse tests

Some of the tests in the gcc.target/arm/cmse directory (eg.
gcc.target/arm/cmse/mainline/bitfield-4.c) are failing when run without
an architecture specified in RUNTESTFLAGS due to them not adding the
option to select an Armv8-M architecture.

This patch fixes the issue by adding the right option from the exp file
so that no architecture fiddling is necessary in the individual tests.

2017-11-17  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/testsuite/
    * gcc.target/arm/cmse/cmse.exp: Add option to select Armv8-M Baseline
    or Armv8-M Mainline when running the respective tests.
    * gcc.target/arm/cmse/baseline/cmse-11.c: Remove architecture check and
    selection.
    * gcc.target/arm/cmse/baseline/cmse-13.c: Likewise.
    * gcc.target/arm/cmse/baseline/cmse-2.c: Likewise.
    * gcc.target/arm/cmse/baseline/cmse-6.c: Likewise.
    * gcc.target/arm/cmse/baseline/softfp.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard-sp/cmse-13.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard-sp/cmse-5.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard-sp/cmse-7.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard-sp/cmse-8.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard/cmse-13.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard/cmse-5.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard/cmse-7.c: Likewise.
    * gcc.target/arm/cmse/mainline/hard/cmse-8.c: Likewise.
    * gcc.target/arm/cmse/mainline/soft/cmse-13.c: Likewise.
    * gcc.target/arm/cmse/mainline/soft/cmse-5.c: Likewise.
    * gcc.target/arm/cmse/mainline/soft/cmse-7.c: Likewise.
    * gcc.target/arm/cmse/mainline/soft/cmse-8.c: Likewise.
    * gcc.target/arm/cmse/mainline/softfp-sp/cmse-5.c: Likewise.
    * gcc.target/arm/cmse/mainline/softfp-sp/cmse-7.c: Likewise.
    * gcc.target/arm/cmse/mainline/softfp-sp/cmse-8.c: Likewise.
    * gcc.target/arm/cmse/mainline/softfp/cmse-13.c: Likewise.
    * gcc.target/arm/cmse/mainline/softfp/cmse-5.c: Likewise.
    * gcc.target/arm/cmse/mainline/softfp/cmse-7.c: Likewise.
    * gcc.target/arm/cmse/mainline/softfp/cmse-8.c: Likewise.

From-SVN: r254860