This is a reland of 21da12a9
Original change's description:
> [Compiler] Remove CompileDebugCode and EnsureBytecode and replace with Compile
> 
> Removes the Compiler::CompileDebugCode and Compiler::EnsureBytecode functions
> and replaces them with a Compiler::Compile(Handle<SharedFunctionInfo> shared)
> function. The code in compiler.cc is refactored to use this function to compile
> the SharedFunctionInfo when compiling a JSFunction.
> 
> Also does some other cleanup:
>  - Removes CompileUnoptimizedFunction and inlines into new Compiler function
>  - Moves code to create top level SharedFunctionInfo into CompilerTopLevel and
>    out of FinalizeUnoptimizedCompile.
> 
> BUG=v8:6409
> 
> Change-Id: Ic54afcd8eb005c17f3ae6b2355060846e3091ca3
> Reviewed-on: https://chromium-review.googlesource.com/613760
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#47394}

TBR=yangguo@chromium.org
TBR=jarin@chromium.org

Bug: v8:6409
Change-Id: If2eae66a85f129e746a5ca5c04935540f3f86b04
Reviewed-on: https://chromium-review.googlesource.com/618886Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47399}