Use 2km instead of 8km data set to calculate cell width

Use 2km instead of 8km data set to calculate cell width. The 8km
data set cause poor cell spacing near the terminus, and an overlap
of the ice thickness with the mesh boundary.

compass/landice/tests/issunguata_sermia/mesh.py

@@ -37,8 +37,8 @@ def __init__(self, test_case):
                             package='compass.landice.tests.issunguata_sermia',
                             target='Issunguata_Sermia.geojson',
                             database=None)
-        self.add_input_file(filename='greenland_8km_2020_04_20.epsg3413.nc',
-                            target='greenland_8km_2020_04_20.epsg3413.nc',
+        self.add_input_file(filename='greenland_2km_2020_04_20.epsg3413.nc',
+                            target='greenland_2km_2020_04_20.epsg3413.nc',
                             database='')
 
     # no setup() method is needed
@@ -55,7 +55,7 @@ def run(self):
         cell_width, x1, y1, geom_points, geom_edges, floodMask = \
             build_cell_width(
                 self, section_name=section_name,
-                gridded_dataset='greenland_8km_2020_04_20.epsg3413.nc')
+                gridded_dataset='greenland_2km_2020_04_20.epsg3413.nc')
 
         build_mali_mesh(
             self, cell_width, x1, y1, geom_points, geom_edges,