Remove unused backpatch_count field

Zend/zend_compile.c

@@ -247,7 +247,6 @@ void zend_oparray_context_begin(zend_oparray_context *prev_context) /* {{{ */
 	CG(context).opcodes_size = INITIAL_OP_ARRAY_SIZE;
 	CG(context).vars_size = 0;
 	CG(context).literals_size = 0;
-	CG(context).backpatch_count = 0;
 	CG(context).fast_call_var = -1;
 	CG(context).try_catch_offset = -1;
 	CG(context).current_brk_cont = -1;

Zend/zend_compile.h

@@ -185,7 +185,6 @@ typedef struct _zend_oparray_context {
 	uint32_t   opcodes_size;
 	int        vars_size;
 	int        literals_size;
-	int        backpatch_count;
 	uint32_t   fast_call_var;
 	uint32_t   try_catch_offset;
 	int        current_brk_cont;