This implements a mechanism to track the exact depth of the operand
stack in full-codegen for every sub-expression visitation. So far we
only tracked the depth at statement level, but not at expression level.
With the introduction of do-expressions it will be possible to construct
local control flow (i.e. break, continue and friends) that target labels
at an arbitrary operand stack depth, making this tracking a prerequisite
for full do-expression support.
R=rossberg@chromium.org,jarin@chromium.org
BUG=v8:4755,v8:4488
LOG=n
Review URL: https://codereview.chromium.org/1706283002
Cr-Commit-Position: refs/heads/master@{#34211}
