This flag enables feedback allocation heuristics to be based on the
function size. The threshold for feedback allocation is set to
12 * bytecode size to roughly mimic the allocation after 12 invocations.

We tried 4 * bytecode size earlier and there were few memory regressions
on real world pages. Speedometer improved by ~1% [1, 2]. This time
trying with a higher factor this time to see if we still have
speedometer improvements without any memory regressions.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=1177124
[2] https://bugs.chromium.org/p/chromium/issues/detail?id=1177241

Change-Id: I39c7d4aaf90b948b07419e4598e2193b8355c067
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2752150
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73369}