Revert^2 "Support using opaque JNI ids"

We weren't handing the fact that encoding jmethodIDs could cause OOM
exceptions in some places in reflection.cc. This could lead to
attempting to use a null jmethodID as if it were a real id. This issue
is fixed by the parent CL.

This reverts commit b476a29a2c.
This reverts commit 3b2905366c.
This Unreverts commit d5d645ffec.
This Unreverts commit 21d5994583.

Reason for revert: Fixed issue causing 004 debuggable flakes
Test: ./test.py --host --jit --debuggable
Bug: 134162467

Change-Id: Iece08ab299cd8a20f8382be7be6c3796858e70eb
23 files changed