Optimize strlen() and in_array() opcodes

[TysonAndre]

• Don't save the opline or check for exceptions if it isn't needed.
  (only affects temporary expressions, not $cv)
• Be more specific about the way to free string operands

// test_strlen(10000000): .402 -> .387 at 2.5GHz
function test_strlen(int $n) {
    $total = 0;
    for ($i = 0; $i < $n; $i++) {
        $total += strlen((string)$i);
    }
    return $total;
}
// test_in_array(40000000): .54 -> .44 at 2.5GHz
function test_in_array(int $n) {
    $total = 0;
    for ($i = 0; $i < $n; $i++) {
        if (in_array($i, [1, 50, 100], true)) {
            $total += $i;
        }
    }
    return $total;
}

[TysonAndre]

@nikic @dstogov - thoughts?

[dstogov]

I'll fix and commit this.

[dstogov]

zend_compare() may throw exception

[dstogov]

These checks make sense only if op1 was IS_REFERENCE

[dstogov]

It doesn't make a lot of sense to over-optimize for exceptional cases.

[dstogov]

FREE_OP1() and exception checks missing

[dstogov]

The most important issue, that in case of Z_TYPE_P(op1) == IS_REFERENCE && opline->extended_value == 0 you don't perform fast zend_hash_find() and fall-back to linear search.

[dstogov]

Merged as f8cf715