Add program counter and instruction to trace decode struct
Add program counter and instruction to trace decode struct

- Instructions in the decode trace vector now record their PC value
- Instruction debug output for instructions from the trace buffer
  now shows the correct program counter value
- Pseudo instruction sequences now record the program counter at
  the start of the fused instruction sequence

$ time rv-jit build/riscv64-unknown-elf/bin/test-loop --trace

rv-jit-0.0.0-prealpha-0

trace-begin pc=0x00000000000100d4
	# 0x00000000000100d4	add         a0, a3, a4
		mov r8, r11
		add r8, r12
	# 0x00000000000100d8	ld          a0, 0(a0)
		mov r8, qword ptr [r8 + 0]
	# 0x00000000000100dc	addi        a4, a4, 8
		add r12, 8
	# 0x00000000000100e0	add         a1, a1, a0
		add r9, r8
	# 0x00000000000100e4	bne         a4, a2, pc - 16
		cmp r12, r10
		je 1f
		mov [rbp + 0], 0x100d4
		jmp term
		1:
	# 0x00000000000100e8	addi        a5, a5, -1
		add r13, -1
	# 0x00000000000100ec	bne         a5, zero, pc - 28
		cmp r13, 0
		jne 1f
		mov [rbp + 0], 0x100f0
		jmp term
		1:
	# 0x00000000000100d0	addi        a4, zero, 0
		mov r12, 0
		mov [rbp + 0], 0x100d4
		term:
trace-end   pc=0x00000000000100d4

total=30000000

real    0m0.029s
user    0m0.024s
sys     0m0.002s

rv8-io/rv8,rv8-io/rv8,rv8-io/rv8