Plex: tutorials ex2 subsumed by tests ex1

Plex: Move tutorials ex12 to tests ex21

The great renaming:

- CHKERRQ() -> PetscCall()
- CHKERRV() -> PetscCallVoid()
- CHKERRMPI() -> PetscCallMPI()
- CHKERRABORT() -> PetscCallAbort()
- CHKERRCONTINUE() -> PetscCallContinue()
- CHKERRXX

The great renaming:

- CHKERRQ() -> PetscCall()
- CHKERRV() -> PetscCallVoid()
- CHKERRMPI() -> PetscCallMPI()
- CHKERRABORT() -> PetscCallAbort()
- CHKERRCONTINUE() -> PetscCallContinue()
- CHKERRXX() -> PetscCallThrow()
- CHKERRCXX() -> PetscCallCXX()
- CHKERRCUDA() -> PetscCallCUDA()
- CHKERRCUBLAS() -> PetscCallCUBLAS()
- CHKERRCUSPARSE() -> PetscCallCUSPARSE()
- CHKERRCUSOLVER() -> PetscCallCUSOLVER()
- CHKERRCUFFT() -> PetscCallCUFFT()
- CHKERRCURAND() -> PetscCallCURAND()
- CHKERRHIP() -> PetscCallHIP()
- CHKERRHIPBLAS() -> PetscCallHIPBLAS()
- CHKERRHIPSOLVER() -> PetscCallHIPSOLVER()
- CHKERRQ_CEED() -> PetscCallCEED()
- CHKERR_FORTRAN_VOID_FUNCTION() -> PetscCallFortranVoidFunction()
- CHKERRMKL() -> PetscCallMKL()
- CHKERRMMG() -> PetscCallMMG()
- CHKERRMMG_NONSTANDARD() -> PetscCallMMG_NONSTANDARD()
- CHKERRCGNS() -> PetscCallCGNS()
- CHKERRPTSCOTCH() -> PetscCallPTSCOTCH()
- CHKERRSTR() -> PetscCallSTR()
- CHKERRTC() -> PetscCallTC()

show more ...

PetscInitialize() and PetscFinalize() wrapped:

- ierr = PetscInitialize();if (ierr) return ierr;
+ CHKERRQ(PetscInitialize());

- ierr = PetscFinalize();
- return ierr;
+ CHKERRQ(PetscFinalize());
+

PetscInitialize() and PetscFinalize() wrapped:

- ierr = PetscInitialize();if (ierr) return ierr;
+ CHKERRQ(PetscInitialize());

- ierr = PetscFinalize();
- return ierr;
+ CHKERRQ(PetscFinalize());
+ return 0;

show more ...

pluck ~1000 low hanging PetscCheckFalse() -> PetscCheck() fruit

chkerr and friends wrapped