This makes sure we only replace load operations for fields on virtual
objects. Even though data flow information for non-virtual (escaping)
allocations is available, it might be inaccurate in certain situations
where object state hasn't been cleared.

R=jarin@chromium.org
TEST=mjsunit/compiler/regress-escape-analysis-indirect

Review-Url: https://codereview.chromium.org/2369953002
Cr-Commit-Position: refs/heads/master@{#39776}