Print hooked sort elements correctly

[Baltoli]

This PR changes the way that we print and serialize collection elements. Previously, we assumed that the elements of collections were uniformly of sort KItem. This is indeed the case for the built-in Map, Set and List sorts, but the assumption breaks down in the presence of custom collection sorts that sort their elements differently (for example, defining a custom Map that requires its keys to only be integers). Terms of these custom sorts are printed incorrectly, with spurious injections into KItem rather than their actual element sorts.

The solution to the problem is to look up the argument sorts of the element constructor when printing and serializing collections; the required information is already present in the binary and just requires a bit of refactoring to access.

This PR makes the following changes:

• Adds @geo2a's minimised test case from Custom hooked Map's element constructor is stripped of sort injection #886 as a new integration test.
• Refactors the generation of argument and return sort tables when the configuration parser is emitted; previously these did not use the emitDataTable infrastructure and so required custom C functions to be written to index into them.
• Look up element sorts using the newly-accessible table when printing collections.

Fixes #886

[gtrepta]

Just noticed this

c09b883#diff-3bc7cdc99077e33c16a7006a9027797a7bb1ae48cd6fbb22117987db7e0e2da6L1334-L1338

It looks like str_type doesn't include the "sort_name_" characters in the array size. I'm assuming it should.

[theo25]

This looks good to me

[Baltoli]

@gtrepta The sort_name_ part is only in the LLVM variable name; e.g.:

@sort_name_SortList = global [9 x i8] c"SortList\00"

Here the type is [9 x i8] and "SortList\00" is 9 characters long as we expect.