Reland "Add a fast path to fetch a field in the caller's declaring class."

This reverts commit 56523a58151aae8586e1213222a123c57c966229.

Reason for revert: Don't use CFA in the new helper.

Flag: EXEMPT optimization

Change-Id: I1245d7d7e10451dc8cd284275aa1265924f1d5d6
8 files changed