Up until now, the debug name of a WebAssembly function was "unknown"
if no name was provided in the name section. With this CL we use the
function index to generate the name "wasm#index" as the debug name.
This debug name is used e.g. for --print-wasm-code or
--trace-turbo-graph


R=clemensh@chromium.org

Change-Id: Ie9b14437fbdef8fd6602eab0d89e415599445099
Reviewed-on: https://chromium-review.googlesource.com/461923
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44230}