In particular FunctionLiteral body. Now clients cannot use
function_literal->body() == nullptr anymore to figure out whether it was
preparsed; but have to check the eager compile hint.

Change-Id: Ia0d3a6b51c6fb7e803157e98a9d224224e03c8a7
Reviewed-on: https://chromium-review.googlesource.com/c/1317811Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57246}