Investigate segfaults due to wrong API usage.

[edg-l]

Sometimes using the api the wrong way, like passing a the wrong type to memref, or other dialects can cause a segfault (i think specially with the pass manager and sometimes verify(?)).

I'll try to have minimal examples when i can, but just wanted to mention i noticed segfaults during my development using melior.

[raviqqe]

Calling mlirLLVM*TypeGet functions without loading the LLVM dialect results in SEGV.