add reftest fv_advection_sine

test/IntegrationTests/refs/fv_advection_sine/fv_advection_sine.toml

+[ScalarEq]
+equation = "advection"
+id = "sine"
+
+[Mesh]
+range = [ 0.0, 1.0 ]
+k = 256
+basis = "lgl_lumped"
+scheme = "FV"
+
+[Output]
+every_iteration = 0
+variables  = [ "u" ]
+aligned_ts = [ 0.25, 0.50, 0.75, 1.0, 1.25, 1.50, 1.75, 2.0 ]
+
+[Evolution]
+tend = 2.2
+cfl = 0.9

test/IntegrationTests/refs/testconfig.toml

@@ -7,6 +7,9 @@ default_abstol = 1e-8
 [advection_sine]
 variables = [ "u" ]
 
+[fv_advection_sine]
+variables = [ "u" ]
+
 [advection_sine_glgl]
 variables = [ "u" ]