LibJS: Add Bytecode::Executable::dump()

Let's have a helper for producing a consistent executable dump instead
of repeating the logic in multiple places.

Userland/Libraries/LibJS/Bytecode/Executable.cpp

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Bytecode/Executable.h>
+
+namespace JS::Bytecode {
+
+void Executable::dump() const
+{
+    for (auto& block : basic_blocks)
+        block.dump(*this);
+    if (!string_table->is_empty()) {
+        outln();
+        string_table->dump();
+    }
+}
+
+}