Moves the creation of shared function infos and the scripts shared function
info array (for top-level code) to be in the FinalizeUnoptimizedCompilation
step when not compiling with Full-codegen. This is needed in order to 
avoid accessing the heap between parse and compile.

BUG=v8:5203

Change-Id: I4063bb91608fa5a0c3d3564767786776a0e4dd03
Reviewed-on: https://chromium-review.googlesource.com/571812
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46731}