Fixed .pool in false block causing an out of range error

Previously something like
```
.if 0 == 1
SomeLabel1:
ldr r1,=0x123
nop
.pool
.endif

.if 1 == 1
SomeLabel2:
ldr r1,=0x456
nop
.pool
.endif
```
Would cause a pool out of range error at the second block.  Now it should assemble as expected.