* add functionality to wasm-module-builder.js to emit the module name
  in the name section.
* extend WasmModule to store the module name length and offset.
* add functionality to module-decoder.cc to decode the module name.
* use the module name for printing stack traces. more uses should
  follow.
* extend one message test to contain a module name.

R=ahaas@chromium.org

Change-Id: I94e6f1f2eb99cb656a92a85bb7afe0742292046f
Reviewed-on: https://chromium-review.googlesource.com/530366Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45846}