core: remove closeCalled check in ServerCallImpl.triggerEvent

Consistent with ServerCallImpl.request(int), do not short-circuit
on the non-volatile closeCalled boolean in triggerEvent. This ensures
ServerCallImpl delegates triggerEvent to the underlying ServerStream,
where stream lifecycle state and serialization are authoritatively
managed in the transport layer.

TAG=agy
CONV=e1bfa5a2-e855-4f79-abdd-ef2b264977be

Author: kannanjgithub

core/src/main/java/io/grpc/internal/ServerCallImpl.java

@@ -256,9 +256,6 @@ public MethodDescriptor<ReqT, RespT> getMethodDescriptor() {
 
   @Override
   public void triggerEvent(Object event) {
-    if (closeCalled) {
-      return;
-    }
     try (TaskCloseable ignore = PerfMark.traceTask("ServerCall.triggerEvent")) {
       PerfMark.attachTag(tag);
       stream.triggerEvent(event);

core/src/test/java/io/grpc/internal/ServerCallImplTest.java

@@ -501,13 +501,14 @@ public void triggerEvent_propagatesToStream() {
   }
 
   @Test
-  public void triggerEvent_afterClose_noop() {
+  public void triggerEvent_afterClose_propagatesToStream() {
     call.close(Status.OK, new Metadata());
     Object event = new Object();
     call.triggerEvent(event);
-    verify(stream, never()).triggerEvent(event);
+    verify(stream).triggerEvent(event);
   }
 
+
   @Test
   public void streamListener_triggerEvent() {
     ServerStreamListenerImpl<Long> streamListener =