Valgrind memcheck errors and warnings

[edsavage]

A number of errors and warnings have been picked up by running all the unit tests (apart from those for seccomp) under valgrind --tool=memcheck .

Log files attached (or soon will be!)

[edsavage]

Valgrind log files..

marple.zip

[edsavage]

I think the better way forward with this is to create multiple GitHub issues, one for each ml-cpp library (apart from seccomp, seccomp doesn't play well with memcheck. I'll leave this issue open and use it to track the sub issues (when created).

[droberts195]

Looks like all the real problems are in the maths library except for one memory leak in CTokenListDataCategorizerTest::(anonymous namespace)::checkMemoryUsageInstrumentation in the model library. I will have a look at the memory leak since it's a test I recently wrote.

(It looks like all the Leak_PossiblyLost problems are due to one-off allocations in system libraries that we cannot control, so I am ignoring those.)