Add type inference for various missing opcodes

[iluuu1994]

No description provided.

[dstogov]

If we don't properly support the SEPARATE yet, it may make sense to remove it and commit everything else.

[iluuu1994]

Thank you, let's do it that way for now. SEPARATE shouldn't be used much in practice anyway.

[dstogov]

Everything looks good, but the inference for SEPARATE may work improperly, because of missing inferences for IS_VAR.

I would suggest to commit this without SEPEARATE.
Please monitor the possible related failures in the "nightly" tests.

[iluuu1994]

Here's the problematic case for SEAPRATE, for future reference.

--TEST--
Trying to write on method return
--FILE--
<?php

function d() {
    return null;
}

function test() {
    d()[] = 2;
    d()[] = 3;
}

for ($i = 0; $i < 10; $i++) {
    test();
}

?>
===DONE===
--EXPECT--
===DONE===

In short, the JIT omits a Z_TYPE_INFO(EX_CV(0)) = IS_NULL; for d()[] = 3; because it incorrectly deduces that the VAR already contains this type. It misses the fact that ASSIGN_DIM may change the type for non-reference VARs.