Add compiler type to CompilerOptions.

Let CompilerOptions hold the information whether it is AOT
or JIT compilation, or Zygote JIT for shared code.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --jit
Test: aosp_taimen-userdebug boots.
Change-Id: Id9200572406f8e43d99b8b61ef0e3edf43b52fff
diff --git a/compiler/driver/compiler_options.cc b/compiler/driver/compiler_options.cc
index 0550075..a5805f9 100644
--- a/compiler/driver/compiler_options.cc
+++ b/compiler/driver/compiler_options.cc
@@ -50,6 +50,7 @@
       dex_files_for_oat_file_(),
       image_classes_(),
       verification_results_(nullptr),
+      compiler_type_(CompilerType::kAotCompiler),
       image_type_(ImageType::kNone),
       compile_art_test_(false),
       baseline_(false),