Move LookupResult into crankshaft as that's now the only place where it's still used

Move LookupResult into crankshaft as that's now the only place where it's still used
Additionally handlify the "transition" field so that GC can stop caring about it.

BUG=

Review URL: https://codereview.chromium.org/935033003

Cr-Commit-Position: refs/heads/master@{#26718}