* src/vm/jit/jit.h (INS_FLAG_ID_SHIFT, INS_FLAG_ID_MASK): Added. We add

* src/vm/jit/jit.h (INS_FLAG_ID_SHIFT, INS_FLAG_ID_MASK): Added. We add
an instruction id to the flags field. This is a first attempt to obtain
an id for ICMDs that is not dependent on any optimizations or
transformations in the compiler. The id is not the same as the bytecode
PC, but it has a fixed relation to the bytecode PC, so it should be
sufficient at least for replacement. This is an intermediate solution
with serious shortcommings, and should be replaced by a true ICMD-to-
bytecode-PC mapping in the future. (For example, the id uses up all
the free bits in the flags field, and it is not protected against
overflow.)

* src/vm/jit/parse.h, src/vm/jit/parse.c: Set the instruction id, and
do not overwrite it when setting other flags.

* src/vm/jit/stack.c: Do not clear the instruction id.

* src/vm/jit/show.c (show_basicblock): Display the instruction id.