Various VM optimizations

Refactored ZVAL flags usage to simplify various checks (e.g. Z_REFCOUNTED(), candidate for GC, etc)

Use STR_COPY() instead of STR_DUP() where possible

Refactor session (incompleted)

Refactored data structures to keep zend_object* instead of a whole zval in some places

Cleanup

Use ZVAL_DEREF() macro

Replaced (Z_TYPE(x) == IS_REFERENCE) with (Z_ISREF(x))

Refactored IS_INDIRECT usage for CV and object properties to support HashTable resizing

More accurate zval comparison

Fixed passing arguments by reference from internal functions

Forgot to remove unused codes

Refactor reference handling

Fixed support for references

Invalid free of args("+")

Handle interned strings as non-refcounted scalars

Fixed NULL pointer dereference

Arguments taken by internal functions using zend_parse_parameters() with "+" and "*" specifications must not be deallocated anymore.

Fixied calling object closures from internal functions

Elements in array could be reference

Fixed user stream filters

Fixed refcount handling

Fixed method argument parsing

Fixed memory leak

Fixed IS_REFERENCE support