MIPS16/GCC: Emit bounds checking as RTL in `casesi'

MIPS16/GCC: Emit bounds checking as RTL in `casesi'

	gcc/
	* config/mips/mips.md (MIPS16_T_REGNUM): Remove constant.
	(casesi): Emit bounds checking as RTL.
	(casesi_internal_mips16_<mode>): Remove bounds checking.

	gcc/testsuite/
	* gcc.target/mips/data-sym-jump.c: Adjust for whitespace changes.
	* gcc.target/mips/pr51513-1.c: New test.
	* gcc.target/mips/pr51513-2.c: New test.

From-SVN: r249207