A WasmModuleObject represents an instance of WebAssembly.Module. It is
called WasmModuleObject internally, so also use that name externally.

We still have a typedef for WasmCompiledModule which will be deprecated
once chromium has been updated to use WasmModuleObject.

R=titzer@chromium.org, adamk@chromium.org

Bug: v8:8238, chromium:912031
Change-Id: I2d7708d4dc183cb4f4714f741b1ea0c153014430
Reviewed-on: https://chromium-review.googlesource.com/c/1362048Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58055}