Bug 1761432 - Part 2: Split out script load request state for when we require loading from source r=smaug

This is used when we explicitly don't want to load cached bytecode. It is
better served by a separate flag in the request than a state.

Differential Revision: https://phabricator.services.mozilla.com/D142042

js/loader/ScriptLoadRequest.cpp

@@ -84,6 +84,7 @@ ScriptLoadRequest::ScriptLoadRequest(ScriptKind aKind, nsIURI* aURI,
     : mKind(aKind),
       mIsCanceled(false),
       mState(State::Fetching),
+      mFetchSourceOnly(false),
       mDataType(DataType::eUnknown),
       mFetchOptions(aFetchOptions),
       mIntegrity(aIntegrity),