port c1d01aea (r37086)

  original commit message:
  Compilation of wasm functions happens before instantiation. Imports are linked afterwards, at instantiation time. Globals and memory are also
  allocated and then tied in via relocation at instantiation time.

  This paves the way for implementing Wasm.compile, a prerequisite to
  offering the compiled code serialization feature.

  Currently, the WasmModule::Compile method just returns a fixed array
  containing the code objects. More appropriate modeling of the compiled module to come.

  Opportunistically centralized the logic on how to update memory
  references, size, and globals, since that logic is the exact same on each
  architecture, except for the actual storing of values back in the
  instruction stream.

BUG=

Review-Url: https://codereview.chromium.org/2100393003
Cr-Commit-Position: refs/heads/master@{#37307}