Clean up the client channel in ByteStreamUploader tests.

This suppresses noisy Netty warnings in the logs.

Closes #8049.

PiperOrigin-RevId: 244840950
diff --git a/src/test/java/com/google/devtools/build/lib/remote/ByteStreamBuildEventArtifactUploaderTest.java b/src/test/java/com/google/devtools/build/lib/remote/ByteStreamBuildEventArtifactUploaderTest.java
index e8995e2..0128d02 100644
--- a/src/test/java/com/google/devtools/build/lib/remote/ByteStreamBuildEventArtifactUploaderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/remote/ByteStreamBuildEventArtifactUploaderTest.java
@@ -50,6 +50,7 @@
 import java.util.Random;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -104,6 +105,8 @@
     // on different threads than the tearDown.
     withEmptyMetadata.detach(prevContext);
 
+    channel.shutdownNow();
+    channel.awaitTermination(5, TimeUnit.SECONDS);
     server.shutdownNow();
     server.awaitTermination();
   }
diff --git a/src/test/java/com/google/devtools/build/lib/remote/ByteStreamUploaderTest.java b/src/test/java/com/google/devtools/build/lib/remote/ByteStreamUploaderTest.java
index fb1a3c3..e58fe7a 100644
--- a/src/test/java/com/google/devtools/build/lib/remote/ByteStreamUploaderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/remote/ByteStreamUploaderTest.java
@@ -124,6 +124,8 @@
     // on different threads than the tearDown.
     withEmptyMetadata.detach(prevContext);
 
+    channel.shutdownNow();
+    channel.awaitTermination(5, TimeUnit.SECONDS);
     server.shutdownNow();
     server.awaitTermination();
   }