aconfig: remove extra new lines and spaces in generated java code

Change the java template to remove the extra new lines and spaces
in generated java code.

Bug: 280833463
Test: atest aconfig.test
Change-Id: I336050540f8a2b0966bf21cf6e034a8fa701458e
diff --git a/tools/aconfig/src/codegen_java.rs b/tools/aconfig/src/codegen_java.rs
index 15eb2d6..79c6eb4 100644
--- a/tools/aconfig/src/codegen_java.rs
+++ b/tools/aconfig/src/codegen_java.rs
@@ -233,8 +233,8 @@
         let expected_featureflagsimpl_content = r#"
         package com.android.aconfig.test;
         import static java.util.stream.Collectors.toMap;
-        import java.util.stream.Stream;
         import java.util.HashMap;
+        import java.util.stream.Stream;
         public final class FeatureFlagsImpl implements FeatureFlags {
             @Override
             public boolean disabledRo() {