Remove unused DexFile UTF-16-based string lookup

DexFile has 2 methods for finding a string ID given an input string:
- MUTF-8 (C null-terminated)
- UTF-16

Only the first one is used in ART.

Bug: 77725588
Test: test-art-host
Change-Id: I2bdaecf4914aa346b77c9a0f6ad17f96abbead9d
2 files changed