Each PreparseData object had at least one pointer to a PodArray for its
serialized scope data. These objects usually have only tens of bytes of
payload. By inlining the byte data we save 3 words per PreparseData object.
This optimization saves 140KB of data on cnn.com.


- Store data_length and inner_length as int32 saving a words on 64bit
- Inline store byte data into PreparseData
- OnHeapConsumedPreparseData directly uses the PreparseData object
- get_inner, set_inner no longer allow Null sentinels

Change-Id: I1f62154d05ea2f98a6574efa738b32a8a84319d5
Reviewed-on: https://chromium-review.googlesource.com/c/1406673Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58751}