stub: Eliminate invalid test cases where different threads were calling close from the thread writing. (grpc#11822)

* Eliminate invalid test cases where different threads were calling close from the thread writing.
* Remove multi-thread cancel/write test

Author: larry-safran

stub/src/test/java/io/grpc/stub/BlockingClientCallTest.java

@@ -195,21 +195,12 @@ public void testCancel() throws Exception {
       assertThat(System.currentTimeMillis() - start).isLessThan(2 * DELAY_MILLIS);
     }
 
-    // write terminated
+    // after cancel tests
     biDiStream = ClientCalls.blockingBidiStreamingCall(channel,  BIDI_STREAMING_METHOD,
         CallOptions.DEFAULT);
-    start = System.currentTimeMillis();
-    delayedCancel(biDiStream, "cancel write");
-
-    // Write interrupted by cancel
-    try {
-      assertFalse(biDiStream.write(30)); // this is interrupted by cancel
-      fail("No exception thrown when write was interrupted by cancel");
-    } catch (StatusException e) {
-      assertEquals(Status.CANCELLED.getCode(), e.getStatus().getCode());
-    }
+    biDiStream.cancel("cancel write", new RuntimeException("Test requested close"));
 
-    // Write after cancel
+    // Write after cancel should throw an exception
     try {
       start = System.currentTimeMillis();
       biDiStream.write(30);
@@ -357,31 +348,19 @@ public void testReadsAndWritesInterleaved_BlockingWrites() throws Exception {
   }
 
   @Test
-  public void testWriteCompleted() throws Exception {
+  public void testWriteAfterCloseThrows() throws Exception {
     testMethod.disableAutoRequest();
     biDiStream = ClientCalls.blockingBidiStreamingCall(channel,  BIDI_STREAMING_METHOD,
         CallOptions.DEFAULT);
 
-    // Verify pending write released
-    long start = System.currentTimeMillis();
-    delayedVoidMethod(DELAY_MILLIS, biDiStream::halfClose);
-    assertFalse(biDiStream.write(1)); // should block until writeComplete is triggered
-    long end = System.currentTimeMillis();
-    assertThat(end - start).isAtLeast(DELAY_MILLIS);
-
     // verify new writes throw an illegalStateException
+    biDiStream.halfClose();
     try {
       assertFalse(biDiStream.write(2));
       fail("write did not throw an exception when called after halfClose");
     } catch (IllegalStateException e) {
       assertThat(e.getMessage()).containsMatch("after.*halfClose.*cancel");
     }
-
-    // verify pending write with timeout released
-    biDiStream = ClientCalls.blockingBidiStreamingCall(channel,  BIDI_STREAMING_METHOD,
-        CallOptions.DEFAULT);
-    delayedVoidMethod(DELAY_MILLIS, biDiStream::halfClose);
-    assertFalse(biDiStream.write(3, 2 * DELAY_MILLIS, TimeUnit.MILLISECONDS));
   }
 
   @Test