Added missing tst file.

basics/advection-diffusion/tests/basics-advection-diffusion-slv.tst

+<?xml version="1.0" encoding="utf-8" ?>
+<test>
+    <description>ADR Solver, advection diffusion DG</description>
+    <parameters>ADR_mesh_aligned.xml ADR_conditions.xml</parameters>
+    <files>
+        <file description="Session File">../basics-advection-diffusion/completed/ADR_mesh_aligned.xml</file>
+        <file description="Session File">../basics-advection-diffusion/completed/ADR_conditions.xml</file>
+    </files>
+    <metrics>
+        <metric type="L2" id="1">
+            <value variable="u" tolerance="1e-8">0.00863475</value>
+        </metric>
+        <metric type="Linf" id="2">
+            <value variable="u" tolerance="1e-8">0.0390366</value>
+        </metric>
+    </metrics>
+</test>