Add dex2oat support for profile based image creation

Allow creating a boot image with only a profile without requiring
any of --compiled-classes, --compiled-methods, or --image-classes.

To do so, you need to pass --profile-file and
--compiler-filter=speed-profile.

Added a test dex2oat_image_test to verify behavior. This test covers:
--compiled-classes
--compiled-methods
--image-classes
--profile-file

Test: test-art-host-gtest-dex2oat_image_test

Bug: 37966211

Change-Id: I36d41b1c6e6560e6b3494b1df7024a4450ed0c0e