Refactor Integer.valueOf() intrinsic implementation.

Prepare for Reference.getReferent() intrinsic implementation
by a refactoring to separate the retrieval of an intrinsic
method's declaring class to its own helper function, rather
than being a part of a larger one.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --jit
Test: aosp_blueline-userdebug boots.
Test: run-gtests.sh
Test: testrunner.py --target --optimizing --jit
Bug: 170286013
Change-Id: Ib6c0e55d0c6fcc932999428f21c51afe32ab7ef2
16 files changed