[Jenkins-SGX] Increase timeout on LibOS tests to 15 minutes

Also increases timeout on LibOS's "udp" test to 50 seconds. It seems to
timeout frequently otherwise.

Jenkinsfiles/Linux-SGX

@@ -40,7 +40,7 @@ pipeline {
                                 make SGX_RUN=1 KEEP_LOG=1 regression
                                 '''
                         }
-                        timeout(time: 5, unit: 'MINUTES') {
+                        timeout(time: 15, unit: 'MINUTES') {
                             sh '''
                                 cd LibOS/shim/test/regression
                                 make SGX=1

LibOS/shim/test/regression/80_udp.py

@@ -4,7 +4,7 @@ from regression import Regression
 loader = sys.argv[1]
 
 # Running udp
-regression = Regression(loader, "udp", None)
+regression = Regression(loader, "udp", None, 50000)
 
 regression.add_check(name="udp",
     check=lambda res: