vm_trace: remove rb_postponed_job_t->flags

This field has been taking up space for 5 years and never used.
Save 8kb of memory on x86-64 for now.  If we ever care about
this flag, we'll simply re-add it.

* vm_trace.c (rb_postponed_job_struct): remove flags
  (postponed_job_register): comment out flags assignment
  [ruby-core:87052] [Misc #14764]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63450 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

vm_trace.c

@@ -1518,7 +1518,6 @@ Init_vm_trace(void)
 }
 
 typedef struct rb_postponed_job_struct {
-    unsigned long flags; /* reserved */
     rb_postponed_job_func_t func;
     void *data;
 } rb_postponed_job_t;
@@ -1555,7 +1554,7 @@ postponed_job_register(rb_execution_context_t *ec, rb_vm_t *vm,
 	return PJRR_INTERRUPTED;
     }
 
-    pjob->flags = flags;
+    /* unused: pjob->flags = flags; */
     pjob->func = func;
     pjob->data = data;