Hand-code the normalized specifier ordering.

For the most part, the enumerated values for specifier types in the
library are already in an acceptable order for normalization.  This
list is part of the API and is expected to be stable.

We can achieve the desired ordering by simply tweaking these values
as needed.  There is also no need to totally order the specifiers
because some combinations are never valid.  This change not only
eliminates a pile of comparatively complex code generation, but
also reduces the overall size of the library somewhat.

Add a new testcase to validate the resulting ordering.