Better hot/cold code splitting

Inline few small opcode handlers into hybrid executor

Embed zend_leave_helper() into hybrid executor to avoid call overhead.

Fixed ISSET/ISEMPTY bit meaning to simplify run-time checks

Marked rarely used opcodes as "cold" (e.g. ADD_CONST_CONST ususaly optimized out).

Fixed conditions

Use "fastcall" calling convention

Remove "hot" mark from JMP(Z|NZ|ZNZ) with IS_CONST operand

Allow extra specialisation for ISSET/ISEMPTY handlers

Reduce overhead of extra-specialization for opcode handler selection.

Merge branch 'PHP-7.2'

* PHP-7.2:
Fixed user-opcode support

Fixed user-opcode support

Allow generation of VM map

Mark exceptional helpers as "cold"

fix ZEND_VM_SET_OPCODE_HANDLER cannot set user opcode handler

Fixed typo

Added VM instrumentation ability

Elimintate duplicate error message

Avoid live range references in opcodes

Don't store the live range of the freed variable for FREE_ON_RETURN
frees, instead look it up at runtime. As this is an extremely
unlikely code

Avoid live range references in opcodes

Don't store the live range of the freed variable for FREE_ON_RETURN
frees, instead look it up at runtime. As this is an extremely
unlikely codepath (in particular, it requires a loop variable with
a throwing destructor), saving the runtime lookup of the live range
is not worth the extra complexity this adds everywhere else.

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Optimize "backup" functions of inlined opcode handlers for size

Added ability to manually sort opcode handlers (not used yet)

Added simple VM instrumentation ability

Avoid inlining of rarely used handlers

fix unknown opcode overflow error

Moved "zval.u2.cache_slot" into free room of "zend_op"