[T] TM/BGRa; Slightly relax tolerance for sigma.

Tests/Data/ThermoMechanics/CreepBGRa/Verification/m2_2Dloadbt/m2_2Dloadbt.prj

@@ -285,7 +285,7 @@
         <vtkdiff>
             <file>m2_2Dloadbt_pcs_0_ts_300_t_0.600000.vtu</file>
             <field>sigma</field>
-            <absolute_tolerance>1e-12</absolute_tolerance>
+            <absolute_tolerance>5e-12</absolute_tolerance>
             <relative_tolerance>0</relative_tolerance>
         </vtkdiff>
         <vtkdiff>