[arm] xfail fp-uint64-convert-double tests

[arm] xfail fp-uint64-convert-double tests

The FP emulation on ARM doesn't take rounding modes into account.  The
tests require hard_float, but that only tests for calls when adding
doubles.  There are arm targets that support hardware adds, but that
emulate conversions.

for  gcc/testsuite/ChangeLog

	* gcc.dg/torture/fp-uint64-convert-double-1.c: Expect fail on
	arm-*-eabi*.
	* gcc.dg/torture/fp-uint64-convert-double-2.c: Likewise.