Remove JQ_DEBUG #define and jq_test binary, simplifying build.

The debugging features previously available via JQ_DEBUG are now
command-line options.

execute.h

@@ -6,8 +6,9 @@
 struct bytecode* jq_compile(const char* str);
 
 typedef struct jq_state jq_state;
+enum {JQ_DEBUG_TRACE = 1};
 
-void jq_init(struct bytecode* bc, jv value, jq_state **);
+void jq_init(struct bytecode* bc, jv value, jq_state **, int flags);
 jv jq_next(jq_state *);
 void jq_teardown(jq_state **);