JitRegister: far code

Some code from the basic blocks is JIT-ed in a "far code" area. This
add JitRegister support for those far code blocks.

The current symbol name is generated with:

~~~cpp
JitRegister::Register(base_address, code_size,
	"JIT_PPC_%08x;%s_%08x", block, name, instruction);
~~~

this format is FlameGraph/stackcollapse friendly and allows to account
the time spent in the far code in the time of the corresponding basic
block and to have information as well as having the type of far code
and the corresponding PowerPC instruction.

However it means that, for other solutions, the time will not be
aggregated into the corresponding basic block. Another solution would
be to use:

~~~cpp
JitRegister::Register(base_address, code_size,
	"JIT_PPC_%08x", block);
~~~

but we would loose all the valuable information about the far code
which might be important.