re PR target/27829 (ICE/abort in shift_op, at config/arm/arm.c:7917 with asm...

re PR target/27829 (ICE/abort in shift_op, at config/arm/arm.c:7917 with asm from testsuite/gcc.dg/pr21255-2-mb.c)

	PR target/27829
	* arm.c (arm_print_operand case 'S'): Validate that the operand is
	a shift operand before calling shift_op.  Avoid redundant call of
	shift_op.

From-SVN: r114265