Unshare popped TT_ENV objects.

Author: matz

Diff for: src/vm.c

@@ -1676,6 +1676,9 @@ mrb_vm_exec(mrb_state *mrb, struct RProc *proc, mrb_code *pc)
 
             ce = mrb->c->cibase + e->cioff;
             while (--ci > ce) {
+              if (ci->env) {
+                mrb_env_unshare(mrb, ci->env);
+              }
               if (ci->acc < 0) {
                 localjump_error(mrb, LOCALJUMP_ERROR_RETURN);
                 goto L_RAISE;
@@ -1727,6 +1730,9 @@ mrb_vm_exec(mrb_state *mrb, struct RProc *proc, mrb_code *pc)
               mrb->c->ci = ci;
               break;
             }
+            if (ci->env) {
+              mrb_env_unshare(mrb, ci->env);
+            }
             ci--;
           }
           break;