Use an opaque format for the frame type marker on the stack, where the
marker is simply shifted left by 1 instead of being a Smi. This allows
us to generate simpler code for frame initialisation, as we can push a
smaller value, decreasing the prologue by 4 bytes and one instruction.

Drive-by: Use the same format for JsFrameMarker.

Change-Id: I812dde9b37869fe20de4148a665d06cf23ce7372
Reviewed-on: https://chromium-review.googlesource.com/443426Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Daniel Clifford <danno@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43347}