test: remove two flaky tests on non-used deprecated path (#897)

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Fixes #<issue_number_goes_here> ☕️

google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1alpha2/StreamWriterTest.java

@@ -834,68 +834,4 @@ public void testExistingClient() throws Exception {
     client.shutdown();
     client.awaitTermination(1, TimeUnit.MINUTES);
   }
-
-  @Test
-  public void testFlushAll() throws Exception {
-    StreamWriter writer =
-        getTestStreamWriterBuilder()
-            .setBatchingSettings(
-                StreamWriter.Builder.DEFAULT_BATCHING_SETTINGS
-                    .toBuilder()
-                    .setElementCountThreshold(2L)
-                    .setDelayThreshold(Duration.ofSeconds(100000))
-                    .build())
-            .build();
-
-    testBigQueryWrite.addResponse(AppendRowsResponse.newBuilder().setOffset(0).build());
-    testBigQueryWrite.addResponse(AppendRowsResponse.newBuilder().setOffset(2).build());
-    testBigQueryWrite.addResponse(AppendRowsResponse.newBuilder().setOffset(3).build());
-
-    ApiFuture<AppendRowsResponse> appendFuture1 = sendTestMessage(writer, new String[] {"A"});
-    ApiFuture<AppendRowsResponse> appendFuture2 = sendTestMessage(writer, new String[] {"B"});
-    ApiFuture<AppendRowsResponse> appendFuture3 = sendTestMessage(writer, new String[] {"C"});
-
-    writer.flushAll(100000);
-
-    assertTrue(appendFuture3.isDone());
-
-    writer.close();
-  }
-
-  @Test
-  public void testFlushAllFailed() throws Exception {
-    StreamWriter writer =
-        getTestStreamWriterBuilder()
-            .setBatchingSettings(
-                StreamWriter.Builder.DEFAULT_BATCHING_SETTINGS
-                    .toBuilder()
-                    .setElementCountThreshold(2L)
-                    .setDelayThreshold(Duration.ofSeconds(100000))
-                    .build())
-            .build();
-
-    testBigQueryWrite.addException(Status.DATA_LOSS.asException());
-    testBigQueryWrite.addException(Status.DATA_LOSS.asException());
-    testBigQueryWrite.addException(Status.DATA_LOSS.asException());
-
-    ApiFuture<AppendRowsResponse> appendFuture1 = sendTestMessage(writer, new String[] {"A"});
-    ApiFuture<AppendRowsResponse> appendFuture2 = sendTestMessage(writer, new String[] {"B"});
-    ApiFuture<AppendRowsResponse> appendFuture3 = sendTestMessage(writer, new String[] {"C"});
-
-    assertFalse(appendFuture3.isDone());
-    try {
-      writer.flushAll(100000);
-      fail("Should have thrown an Exception");
-    } catch (Exception expected) {
-      if (expected.getCause() instanceof com.google.api.gax.rpc.DataLossException) {
-        LOG.info("got: " + expected.toString());
-      } else {
-        fail("Unexpected exception:" + expected.toString());
-      }
-    }
-
-    assertTrue(appendFuture3.isDone());
-
-    writer.close();
-  }
 }