Revert "Change the region of acceptance tests to us-west4 (#1329)" (#1330)

This reverts commit 27a2816.

Author: isha97

spark-bigquery-connector-common/src/test/java/com/google/cloud/spark/bigquery/acceptance/AcceptanceTestConstants.java

@@ -19,7 +19,7 @@
 
 public class AcceptanceTestConstants {
 
-  public static final String REGION = "us-west4";
+  public static final String REGION = "us-west1";
   public static final String DATAPROC_ENDPOINT = REGION + "-dataproc.googleapis.com:443";
   public static final String PROJECT_ID =
       Preconditions.checkNotNull(