[ARM] instr. with pc writes are not part of jump group

[Rot127]

An instruction which writes to pc should be part of the jump group.

Similar logic is added for pop instructions which write to pc ( 4fc80d8)

As an example, this mov should be of the jump group.

./cstool -d thumb 8746
 0  87 46  mov	pc, r0
	ID: 28 (mov)
	op_count: 2
		operands[0].type: REG = r15
		operands[0].access: WRITE
		operands[1].type: REG = r0
		operands[1].access: READ
	Registers read: r0
	Registers modified: r15
	Groups: IsThumb