Set a timeout on the shim unit tests; this is hanging in CI on an experimental branch.

Jenkinsfiles/Linux-SGX

@@ -42,12 +42,14 @@ pipeline {
                                 '''
 			}
 			*/
-                        sh '''
-                            cd LibOS/shim/test/regression
-			    make SGX=1
-			    make SGX_RUN=1			    
-                            make SGX_RUN=1 regression
+			timeout(time: 5, unit: 'MINUTES') {		    			
+                            sh '''
+                                cd LibOS/shim/test/regression
+			        make SGX=1
+			        make SGX_RUN=1			    
+                                make SGX_RUN=1 regression
                             '''
+			}    
                         sh '''
                             cd LibOS/shim/test/apps/python
 			    make SGX=1