When node splitting is enabled new nodes could be created during scheduling.
The Scheduler::node_data_ and Schedule::nodeid_to_block_ zone vectors
reserve enough space for the node count before splitting, however will
have to reallocate space when node splitting occurs. The vectors double
in space by default, meaning the peak zone usage is 3x the required amount
for these vectors as soon as a single node is split. Avoid this in the
common case by reserving 10% extra space for split nodes. The value
10% was choosen since it covers 98.7% of the optimized functions in Octane.

BUG=chromium:700364

Change-Id: Ibabd8d04cffd1eb08cc3b8a12b76892208ef3288
Reviewed-on: https://chromium-review.googlesource.com/458425
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44153}