Fix gcc.dg/torture/fp-int-convert.h for excess precision after PR c/87390.

Fix gcc.dg/torture/fp-int-convert.h for excess precision after PR c/87390.

As reported in
<https://gcc.gnu.org/ml/gcc-patches/2018-09/msg01684.html>, some
fp-int-convert tests fail after my fix for PR c/87390, in Arm /
AArch64 configurations where _Float16 uses excess precision by
default.  The issue is comparisons of the results of a conversion by
assignment (compile-time or run-time) from integer to floating-point
with the original integer value; previously this would compare against
an implicit compile-time conversion to the target type, but now, for
C11 and later, it compares against an implicit compile-time conversion
to a possibly wider evaluation format.  This is fixed by adding casts
to the test so that the comparison is with a value converted
explicitly to the target type at compile time, without any use of a
wider evaluation format.

	PR c/87390
	* gcc.dg/torture/fp-int-convert.h (TEST_I_F_VAL): Convert integer
	values explicitly to target type for comparison.

From-SVN: r264696