This used to be a node package. Let's make it become regular commonjs devtools modules.
This will make it trivial to migrate this to ES Modules.
Also possibly make this code become the unique layer in m-c on top of the source-map package.
We no longer use webpack to build the two bundles (index.js and worker.js),
instead, we are using the toolkit worker loader (require.js) in order to load
all this code without any build step.
As this is no longer a node package, I removed node-specific modules (assertRoot/wasmAsset)
and simplify the definition of wasm file URIs as they are now fixed.
Also moving the debugger to load internal "devtools/client/shared/source-map/source-map.js"
module in jest as running the Web Worker instantiated by source-map/index.js is too complex.
Differential Revision: https://phabricator.services.mozilla.com/D159115
Julian Descottes