Add Regression Test for Undefined UDQ Variables

Undefined UDQs get the value in UDQPARAM(3).  The UDQ-01 test model
triggers an action block if and only if we implement that behaviour.

regressionTests.cmake

@@ -585,6 +585,13 @@ add_test_compareECLFiles(CASENAME reg_smry_in_fld_udq
                          DIR udq_actionx
                          TEST_ARGS --enable-tuning=true)
 
+add_test_compareECLFiles(CASENAME udq_undefined_2
+                         FILENAME UDQ-01
+                         SIMULATOR flow
+                         ABS_TOL ${abs_tol}
+                         REL_TOL ${rel_tol}
+                         DIR actionx)
+
 add_test_compareECLFiles(CASENAME cskin-01
                          FILENAME CSKIN-01
                          SIMULATOR flow