test: remove the category from the base class for all integration tests (#616)

Removes the category from the base class for all integration tests so they are not excluded
from multiple builds, as the result is that both the category of the base class as well as
the concrete class are applied.

Author: olavloite

src/test/java/com/google/cloud/spanner/jdbc/ITAbstractJdbcTest.java

@@ -18,7 +18,6 @@
 
 import com.google.cloud.spanner.Database;
 import com.google.cloud.spanner.GceTestEnvConfig;
-import com.google.cloud.spanner.IntegrationTest;
 import com.google.cloud.spanner.IntegrationTestEnv;
 import com.google.cloud.spanner.connection.AbstractSqlScriptVerifier;
 import com.google.cloud.spanner.connection.ConnectionOptions;
@@ -38,10 +37,8 @@
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.ClassRule;
-import org.junit.experimental.categories.Category;
 
 /** Base class for all JDBC integration tests. */
-@Category(IntegrationTest.class)
 public class ITAbstractJdbcTest {
   protected class ITJdbcConnectionProvider
       implements com.google.cloud.spanner.connection.AbstractSqlScriptVerifier