rb_ractor_thread_list() only for current ractor

so that no need to lock the ractor.

ractor.c

@@ -2120,35 +2120,24 @@ rb_ractor_living_thread_num(const rb_ractor_t *r)
     return r->threads.cnt;
 }
 
+// only for current ractor
 VALUE
-rb_ractor_thread_list(rb_ractor_t *r)
+rb_ractor_thread_list(void)
 {
+    rb_ractor_t *r = GET_RACTOR();
     rb_thread_t *th = 0;
-    VALUE *ts;
+    VALUE ary = rb_ary_new();
-    int ts_cnt;
-
-    RACTOR_LOCK(r);
-    {
-        ts = ALLOCA_N(VALUE, r->threads.cnt);
-        ts_cnt = 0;
 
     ccan_list_for_each(&r->threads.set, th, lt_node) {
         switch (th->status) {
           case THREAD_RUNNABLE:
           case THREAD_STOPPED:
           case THREAD_STOPPED_FOREVER:
-                ts[ts_cnt++] = th->self;
+            rb_ary_push(ary, th->self);
           default:
             break;
         }
     }
-    }
-    RACTOR_UNLOCK(r);
-
-    VALUE ary = rb_ary_new();
-    for (int i=0; i<ts_cnt; i++) {
-        rb_ary_push(ary, ts[i]);
-    }
 
     return ary;
 }

ractor_core.h

@@ -209,7 +209,7 @@ void rb_ractor_send_parameters(rb_execution_context_t *ec, rb_ractor_t *g, VALUE
 VALUE rb_thread_create_ractor(rb_ractor_t *g, VALUE args, VALUE proc); // defined in thread.c
 
 int rb_ractor_living_thread_num(const rb_ractor_t *);
-VALUE rb_ractor_thread_list(rb_ractor_t *r);
+VALUE rb_ractor_thread_list(void);
 bool rb_ractor_p(VALUE rv);
 
 void rb_ractor_living_threads_init(rb_ractor_t *r);

thread.c

@@ -2728,7 +2728,7 @@ VALUE
 rb_thread_list(void)
 {
     // TODO
-    return rb_ractor_thread_list(GET_RACTOR());
+    return rb_ractor_thread_list();
 }
 
 /*