Extract a helper function for handling ASSIGN_DIM and ASSIGN_*
with ASSIGN_DIM ev uniformly. Previously the code was copy pasted
for each ASSIGN_* op, but the variable names were not correctly
adjusted (tmp vs orig), so the type inference result was wrong.
Also sligthly improve handling:
* Result cannot be false, will always be converted to array.
* If the dim is a CONST string operand, we don't have to assume
numeric strings.
* If the inserted value may be undef, the array may contain null.
* Add FETCH_LIST to inference
* Restrict JMP_SET/COALESCE result type
* Fix typos in range inference
* Add const annotations in zend_ssa.h
* For pi statements dump the associated predecessor block
* If type can be both true and false, dump bool instead
Yield-by-ref defs a ref var, yield-by-var only defs an rc1/rcn var
if rc inference is used.
Also move BIND_LEXICAL where it belongs in DFG construction.
This opcodes inserts a local CV into the closure static variable
table. This replaces the previous mechanism of having static
variables marked as LEXICAL, which perform a symtable lookup
during copying.
This means a) functions which contain closures no longer have to
rebuild their symtable (better performance) and b) we can now track
used variables in SSA.
