JIT: add ZEND_BW_NOT handler for integer operands

[adapik]

ZEND_BW_NOT is currently the only bitwise opcode without a JIT handler: BW_OR, BW_AND, BW_XOR, SL and SR are all compiled. As a result, an expression such as ~$a & $b breaks the compiled code with a call into the VM handler, and values kept in registers have to be spilled around it. This and-not combination shows up in bit-manipulation code such as hash functions, checksums and other algorithms.

This PR adds a handler for the case where the operand is known to be int. Any other operand type (string, float, bool, null, array, object, undefined, constant) is not handled and keeps going through the VM handler, so behaviour,
warnings and TypeError messages are unchanged.

Release build (-O2), x86-64, best of several runs, 20M iterations of
$s ^= (~$a & $b) ^ ($i << 3):

JIT	before	after
tracing	0.037s	0.011s
function	0.036s	0.025s

This is a micro-benchmark that isolates the affected pattern.