Use jazzct for (S)CT checking

[J08nY]

The (S)CT checking in Jasmin is now done via the jazzct standalone checker (https://github.com/jasmin-lang/jasmin/pull/766). Thus, Makefile.checksct should use that (it is currently broken, AFAICT).

The blockers are:

• No support for -I include paths in the jazzct binary, only via JASMINPATH.
• For DOIT checking only (https://github.com/jasmin-lang/jasmin/pull/736). No support for -lea, -lazy-regalloc or -noinsertarraycopy in jazzct, as these matter when checking is done after many compiler passes (and some primitives do not compile without them).