Refs #8807 Add some system tests for ConvFit.
Revert "Refs #8807 Add some system tests for ConvFit."

This reverts commit d1b071c94d610c017b02166bdbd27da8a9a12a06.
Revert "Revert "Refs #8807 Add some system tests for ConvFit.""

This reverts commit a2137e58d2ccbdce33d9a24859a8e30f9fe698d0.
Refs #8800 Relax tolerance.
Refs #8803 Update tolerance levels.
Refs #8800 Update with more accurate parameters for IRIS.
Refs #8803 Update with finer parameters for IRIS.
Merge remote-tracking branch 'origin/feature/8803_convfit_sys_tests'