[RFC] Add matchaddpos()-related vim patches. [vim-patch: 7.4.330, 7.4.334, 7.4.343, 7.4.344, 7.4.362]

Adds patches 7.4.330, 334, 344 and 362.
Ah! This might have been the cause of the error in the test. `m->pos` was filled with garbage.