scheduler.py: Update the name of the default scheduler. (#26758)

Signed-off-by: Ryan Li <ryanli@ryanli.org>

vllm/engine/arg_utils.py

@@ -1742,11 +1742,6 @@ class EngineArgs:
                 self.enable_prefix_caching = incremental_prefill_supported
                 logger.info("(%s) prefix caching by default", action)
 
-        # V1 should use the new scheduler by default.
-        # Swap it only if this arg is set to the original V0 default
-        if self.scheduler_cls == EngineArgs.scheduler_cls:
-            self.scheduler_cls = "vllm.v1.core.sched.scheduler.Scheduler"
-
         # When no user override, set the default values based on the usage
         # context.
         # Use different default values for different hardware.