vhpi: Add get/set support for selected names

vhpi: Add get/set support for selected names

Inhomogenous types are create scopes instead of signals. Additionally,
inhomogenous arrays have nested scopes for their elements. Add the
necessary machinery to determine the scope for a name/objDecl, and look
up the signal at the final level.

In the style of vhpi7, assign a value to each element of the test
records, and try to change them. To avoid needing to repeat the same
code while recursing through records, we just print out the values and
check them against the golden output. We cheat a bit for
multidimensional arrays because array properties are checked properly in
vhpi7.