Adding awaitTermination in our tests tear down.

This is to prevent this error:

SEVERE: *~*~*~ Channel io.grpc.internal.ManagedChannelImpl-56 for target directaddress:///io.grpc.inprocess.InProcessSocketAddress@3ecbfba1 was not shutdown properly!!! ~*~*~*
    Make sure to call shutdown()/shutdownNow() and awaitTermination().

TESTED=ran tests
RELNOTES: None
PiperOrigin-RevId: 185020683
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 21e4438..1991d7d 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
@@ -112,6 +112,7 @@
   public void tearDown() throws Exception {
     server.shutdownNow();
     retryService.shutdownNow();
+    server.awaitTermination();
   }
 
   @Test(timeout = 10000)
diff --git a/src/test/java/com/google/devtools/build/lib/remote/GrpcRemoteCacheTest.java b/src/test/java/com/google/devtools/build/lib/remote/GrpcRemoteCacheTest.java
index 0b220aa..5b342e8 100644
--- a/src/test/java/com/google/devtools/build/lib/remote/GrpcRemoteCacheTest.java
+++ b/src/test/java/com/google/devtools/build/lib/remote/GrpcRemoteCacheTest.java
@@ -121,6 +121,7 @@
   @After
   public void tearDown() throws Exception {
     fakeServer.shutdownNow();
+    fakeServer.awaitTermination();
   }
 
   private static class CallCredentialsInterceptor implements ClientInterceptor {