Cleaned up the testCopyAssignment and testConversion functions to enable clean use of the the Anti Tri Diag Matrix setup and check.

	Changed the name of "setupMatrix" to "setupTriDiagMatrix".
	Added a setup and check for the AntiTrigDiagMatrix.
	Commented out the TriDiagMatrix setups and checks in order to verify the validity of the new AntiTriDiagMatrix.

It does not have any effect on recent builds and we explicitly set
-march=native -mtune=native later in the file.

Distributed linear solvers

See merge request mmg/tnl-dev!8