MIPS16/opcodes: Fix PC-relative operation delay-slot adjustment

MIPS16/opcodes: Fix PC-relative operation delay-slot adjustment

Complement commit dd8b7c222e0e ("MIPS: mips16e jalrc/jrc opcodes"),
<https://sourceware.org/ml/binutils/2005-07/msg00349.html>, and stop the
disassembler making a delay-slot adjustment for PC-relative operations
following either MIPS16e compact jumps, or undefined RR/J(AL)R(C)
encodings that have the `l' (link) and `ra' (source register is `ra')
bits set both at a time.  Adjust code description for accuracy.  Add a
suitable test case.

	opcodes/
	* mips-dis.c (print_mips16_insn_arg): Avoid delay-slot
	adjustment for PC-relative operations following MIPS16e compact
	jumps or undefined RR/J(AL)R(C) encodings.

	binutils/
	* testsuite/binutils-all/mips/mips16-pcrel.d: New test.
	* testsuite/binutils-all/mips/mips16-pcrel.s: New test source.
	* testsuite/binutils-all/mips/mips.exp: Run the new test.