Refactor of function call codegen. Separate codegen for C and jq calls.

execute.c

@@ -411,9 +411,8 @@ jv jq_next() {
     }
       
     case CALL_BUILTIN_1_1: {
-      assert(*pc == 1); // no closure args allowed
+      assert(*pc == 2);
       pc++; // skip nclosures
-      pc++; // skip level
       stackval top = stack_pop();
       cfunc_input[0] = top.value;
       struct cfunction* func = &frame_current_bytecode(&frame_stk)->globals->cfunctions[*pc++];
@@ -429,9 +428,8 @@ jv jq_next() {
     }
 
     case CALL_BUILTIN_3_1: {
-      assert(*pc == 1); // no closure args allowed
+      assert(*pc == 4); // no closure args allowed
       pc++; // skip nclosures
-      pc++; // skip level
       stackval top = stack_pop();
       jv a = stack_pop().value;
       jv b = stack_pop().value;