This CL consolidates ownership of parameters used to compile code (which
we always specialize) in 2 places:
- ModuleEnv for compile-time data
- WasmCompiledModule for runtime data

The parameters in question are: memory size and start; globals start; 
address of indirect function tables (and their signatures, respectively); 
and address to be used for wasm call sites.

Ideally, we'd collapse this down to one place, however, we need
specialization data to survive serialization. We can achieve this we get off 
the GC heap and use a different wasm code serializer.

The CL:
- removes aliasing of parts of the specialization data, and moves
to using ModuleEnv as a token of passing around compile-time data, instead
of a mixture of ModuleEnv, WasmInstance, and some other structures. ModuleEnv
is responsible for providing a consistent view of the specialization data,
e.g. valid memory sizes (multiples of page size), and matching sized function
tables and signatures.

- removes WasmInstance, as its data is now contained by ModuleEnv.

- removes ModuleBytesEnv. We now pass the wire bytes explicitly. They can't
always be assumed as present (e.g. streaming compilation), and probably more
refactoring may need to happen once streaming compilation lands and we
better understand our dependencies.

Change-Id: Id7e6f2cf29e51b5756eee8b6f8827fb1f375e5c3
Reviewed-on: https://chromium-review.googlesource.com/592531
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47229}