WebContent+LibWeb+LibJS: Simplify injection of JS console globals

Instead of creating a new global object and proxying everything through
it, we now evaluate console inputs inside a `with` environment.

This seems to match the behavior of WebKit and Gecko in my basic
testing, and removes the ConsoleGlobalObject which has been a source of
confusion and invalid downcasts.

The globals now live in a class called ConsoleGlobalObjectExtensions
(renamed from ConsoleGlobalObject since it's no longer a global object).

To make this possible, I had to add a way to override the initial
lexical environment when calling JS::Interpreter::run(). This is plumbed
via Web::HTML::ClassicScript::run().

Userland/Libraries/LibJS/Interpreter.cpp

@@ -35,7 +35,7 @@ Interpreter::Interpreter(VM& vm)
 }
 
 // 16.1.6 ScriptEvaluation ( scriptRecord ), https://tc39.es/ecma262/#sec-runtime-semantics-scriptevaluation
-ThrowCompletionOr<Value> Interpreter::run(Script& script_record)
+ThrowCompletionOr<Value> Interpreter::run(Script& script_record, JS::GCPtr<Environment> lexical_environment_override)
 {
     auto& vm = this->vm();
 
@@ -62,6 +62,10 @@ ThrowCompletionOr<Value> Interpreter::run(Script& script_record)
     // 7. Set the LexicalEnvironment of scriptContext to globalEnv.
     script_context.lexical_environment = &global_environment;
 
+    // Non-standard: Override the lexical environment if requested.
+    if (lexical_environment_override)
+        script_context.lexical_environment = lexical_environment_override;
+
     // 8. Set the PrivateEnvironment of scriptContext to null.
 
     // NOTE: This isn't in the spec, but we require it.