We use o suffix to indicate record form instuctions,
(as it is similar to dot '.' in mne?)
This was fine before, as we did not support XO-form.
However, with https://reviews.llvm.org/D66902,
we now have XO-form support.
It becomes confusing now to still use 'o' for record form,
and it is weird to have something like 'Oo' .
This patch rename all 'o' instructions to use '_rec' instead.
Also rename isDot to isRecordForm.