[ARM] Fix size-optimization-ieee testcase failure

[ARM] Fix size-optimization-ieee testcase failure

On some version of dejagnu, options in RUNTESTFLAGS are appended to the
command-line and thus any -mfloat-abi=softfp or -mfloat-abi=hard in
there overwrite the -mfloat-abi=soft in the dg-options for
size-optimization-ieee-* tests. Test is still run though because
arm_soft_ok returns true if -mfloat-abi=soft is accepted, even if the
file is not compiled for softfloat due to a later -mfloat-abi on the
command line.

This patch adds a dg-skip-if to those tests to ensure they are not run
in softfp or hard mode.

2018-12-21  Thomas Preud'homme  <thomas.preudhomme@linaro.org>

    gcc/testsuite/
    * gcc.target/arm/size-optimization-ieee-1.c: Skip if passing
    -mfloat-abi=softfp or -mfloat-abi=hard.
    * gcc.target/arm/size-optimization-ieee-2.c: Likewise.
    * gcc.target/arm/size-optimization-ieee-3.c: Likewise.

From-SVN: r267323