Update core instruction syntax to Rev32

Update core instruction syntax to Rev32

Many instructions added and a few changed structure.

Workarounds:
- Some operands can be enabled by either one of two
  capabilities.  The spv_operand_desc_t does not handle that
  now. For now just select the first one.

Fixes to tests:
- OpLoopMerge now takes a mandatory continue target.
- OpTypePipe drops the type argument.  Pipes are opaque.
- OpLine no longer takes a target ID argument.

The ID validator was fixed the OpLine and OpTypePipe
changes.  Those were the only ID validator tests affected.

The patch to the spec doc generator was updated so it handles
the two-capability case, even if in an hacky way.