Rewrite image type in CompilerOptions.

Prepare for introduction of boot image extension.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: Pixel 2 XL boots.
Change-Id: Id007c4aeb4ada84fe65c1148fdf67e8a412e5b74
diff --git a/dex2oat/linker/image_test.h b/dex2oat/linker/image_test.h
index 9d1a4e7..9ef2875 100644
--- a/dex2oat/linker/image_test.h
+++ b/dex2oat/linker/image_test.h
@@ -216,11 +216,10 @@
   // TODO: compile_pic should be a test argument.
   std::unique_ptr<ImageWriter> writer(new ImageWriter(*compiler_options_,
                                                       kRequestedImageBase,
-                                                      /*compile_app_image*/false,
                                                       storage_mode,
                                                       oat_filename_vector,
                                                       dex_file_to_oat_index_map,
-                                                      /*dirty_image_objects*/nullptr));
+                                                      /*dirty_image_objects=*/ nullptr));
   {
     {
       jobject class_loader = nullptr;