Remove packing for bools.

[ChrisPenner]

Overview

On trunk, primitive operations return a 'tag', then we run a separate branch instruction which returns the equivalent Unison bool datatype.

This change alters primitive ops which return bools to simply put the correct unison bool directly onto the stack, saving an instruction on each boolean op.

Implementation notes

• Alter primitive ops to push bools directly to the stack
• Add some missing instructions to avoid the need for multiple instructions, e.g. NEQN instead of EQLN >>> NOTB
• Remove all the now-unnecessary branches.

Test coverage

Existing transcripts