Add a util class for constructing class loader context for primary dex.

This class is rewritten from
frameworks/base/services/core/java/com/android/server/pm/dex/DexoptUtils.java
with logic that is more readable.

Also:
- Add reflection wrappers that are used in this CL.

Bug: 229268202
Test: atest ArtServiceTests
Ignore-AOSP-first: ART services
Change-Id: I600da98585ff9aa2806bed4d18d6ce5eb6422d1a
8 files changed