Fix ternary parser bug

[s-hadinger]

Fix #396

Details:

The Berry parser does simple optimization in the following pattern:

def f() var a = 1 a = a + 2 end

The raw bytecode generated is:

0000  LDCONST	R0	K0
0001  ADD	R1	R0	K1
0002  MOVE	R0	R1
0002  RET	0

but the optimizer saves the MOVE:

0001  ADD	R1	R0	K1
0002  MOVE	R0	R1
# replaced by
0001  ADD	R0	R0	K1

storing directly the result in R0 instead of storing into a temporary R1 that is discarded right after.

In the case of the ternary operator, only the last ADD is patched, not the first one.

Fix: I added a lastjmp information which point to the further position in PC where a JMP lands. This optimization should not happen at the beginning of a new string of code starting from the target of a JMP.