ART: Add more ThreadOffset in Mir2Lir and backends

This duplicates all methods with ThreadOffset parameters, so that
both ThreadOffset<4> and ThreadOffset<8> can be handled. Dynamic
checks against the compilation unit's instruction set determine
which pointer size to use and therefore which methods to call.

Methods with unsupported pointer sizes should fatally fail, as
this indicates an issue during method selection.

Change-Id: Ifdb445b3732d3dc5e6a220db57374a55e91e1bf6