storage - do not eager parse extension storage (fix #163446)

[bpasero]

This is for #163446. As it turns out, the storage service will not do any JSON.parse eagerly. Storage values are primitives but never objects. However, we seem to be doing some JSON.parse from here specifically for extensions:

vscode/src/vs/platform/extensionManagement/common/extensionStorage.ts

Line 151 in 5f383ab

return JSON.parse(jsonValue);

I tried to reduce calls to this method in the renderer in favour of the new getExtensionStateRaw and move the parsing to the extension host to avoid large stalls in the renderer. In addition, I am logging a warning when an extension storage value exceeds 500kb.

@sandy081 there are still some calls to getExtensionState in your area which are probably needed but I think they also happen from another process?

//cc @alexdima

[sandy081]

Those calls to getExtensionState are for syncing extension state. In Desktop, this is called in shared process, where as in web it is still in same process.