Prepare MASM for better runtime string handling

Keep the run-time functions as-is by taking String pointers and use a little
bit of inline assembly to resolve the string ids to string pointers, by
adding a runtimeStrings array pointer next to the lookups in the context
(similar mechanism).

Change-Id: Ib5a70bdf47fef7c447d646ccfe03f3dc30d39f20
Reviewed-by: Lars Knoll <lars.knoll@digia.com>