[SH] Add FPUL usage testcase

[Oleg Endo]

Hi,

I'd like to add an SH target testcase which is supposed to check the
usage of the FPUL register when float values are treated as int and vice
versa.  Does this make sense?

Tested against rev 185360 with the usual 

make -k check RUNTESTFLAGS="--target_board=sh-sim
\{-m2/-ml,-m2/-mb,-m2a-single/-mb,
-m4-single/-ml,-m4-single/-mb,
-m4a-single/-ml,-m4a-single/-mb}"

and individually with some of the sub-target variations that do not have
an FPU (for which the test is skipped).

Cheers,
Oleg


testsuite/ChangeLog

        * gcc.target/sh/fpul-usage-1.c: New.