Propagate memo on continue-as-new in the test server (#2943)

The in-memory test server carried over search attributes and header on
continue-as-new but dropped the memo, so a workflow that sets a memo on
continue-as-new could not read it back on the new run under the test
environment even though it works against a real server.

Set the memo on the ContinuedAsNew event attributes and on the new run
start request, mirroring the existing search attribute handling, and
extend ContinueAsNewTest to assert the memo is visible after
continue-as-new.

Closes #2863

Author: aditya-786

temporal-sdk/src/test/java/io/temporal/workflow/ContinueAsNewTest.java

@@ -77,6 +77,13 @@ public int execute(int count, String continueAsNewTaskQueue) {
         assertEquals(5, Workflow.getInfo().getRetryOptions().getMaximumAttempts());
         assertEquals("foo1", Workflow.getTypedSearchAttributes().get(CUSTOM_KEYWORD_SA));
       }
+      // The memo is set on every continue-as-new below, so every run after the
+      // first one should observe it once the test server propagates it.
+      if (count <= INITIAL_COUNT - 2) {
+        assertEquals("MyValue", Workflow.getMemo("myKey", String.class));
+      } else {
+        Assert.assertNull(Workflow.getMemo("myKey", String.class));
+      }
       if (count == 0) {
         assertEquals(continueAsNewTaskQueue, taskQueue);
         return 111;

temporal-test-server/src/main/java/io/temporal/internal/testservice/StateMachines.java

@@ -1467,6 +1467,9 @@ private static void continueAsNewWorkflow(
     if (d.hasSearchAttributes()) {
       a.setSearchAttributes(d.getSearchAttributes());
     }
+    if (d.hasMemo()) {
+      a.setMemo(d.getMemo());
+    }
     a.setNewExecutionRunId(UUID.randomUUID().toString());
     HistoryEvent event =
         HistoryEvent.newBuilder()

temporal-test-server/src/main/java/io/temporal/internal/testservice/TestWorkflowService.java

@@ -1757,6 +1757,9 @@ public String continueAsNew(
     if (ea.hasSearchAttributes()) {
       startRequestBuilder.setSearchAttributes(ea.getSearchAttributes());
     }
+    if (ea.hasMemo()) {
+      startRequestBuilder.setMemo(ea.getMemo());
+    }
     StartWorkflowExecutionRequest startRequest = startRequestBuilder.build();
     lock.lock();
     Optional<Failure> lastFail =