Subzero: Add a "make check-spec" target.

Subzero: Add a "make check-spec" target.

"make -f Makefile.standalone check-spec" will translate and run all the spec2k components for a given target.

The advantages are that this can be done all within the subzero directory, and the spec components can be run in parallel via "make -j" (particularly helpful for arm32/qemu).

Default target is x8632, and arm32 is also available.

Example:

  make -j32 -f Makefile.standalone check-spec TARGET=arm32 SPEC="-O2 --filetype=iasm"

Also removes unnecessary tab characters from the makefile, fixes >80-column lines, and gives more consistent indentation.

BUG= none
R=jpp@chromium.org

Review URL: https://codereview.chromium.org/1413033009 .