Complete Centrallix-Lib test suite

[sheesania]

Centrallix-Lib modules that still need test completion:

• mtsession module
• newmalloc module
• stparse module
• xarray module
• xhandle module
• xhash module
• xhashqueue module
• xringqueue module
• xstring module

[Lightning11wins]

Looks like I made this problem worse by expanding util.h without adding any tests.

I'll see if I can make some progress on improving it.

[Lightning11wins]

I just put up a PR with tests for all the new util.h, functions, as well as most functions in xarray.h and xstring.h. I'll add tests for cluster.h soon.