LibJS: Move global "should dump bytecode" flag into LibJS

This will allow us to trigger bytecode executable dumps when generating
bytecode inside LibJS as well, not just in clients like js and test-js.

Userland/Libraries/LibJS/Bytecode/Interpreter.cpp

@@ -17,6 +17,7 @@
 namespace JS::Bytecode {
 
 static Interpreter* s_current;
+bool g_dump_bytecode = false;
 
 Interpreter* Interpreter::current()
 {

Userland/Libraries/LibJS/Bytecode/Interpreter.h

@@ -85,4 +85,6 @@ private:
     Handle<Exception> m_saved_exception;
 };
 
+extern bool g_dump_bytecode;
+
 }