Make snapshot unit-test less failure-prone

Author: pjdarton

src/test/java/io/jenkins/plugins/credentials/secretsmanager/factory/BaseAwsJsonCredentialsSnapshotTakerTest.java

@@ -111,10 +111,15 @@ public void snapshotGivenInstanceThenCreatesSnapshot() throws Exception {
         final Method[] allMethods = credentialBeingSnapshotted.getDeclaredMethods();
         final Map<Method, Object> expectedResults = new IdentityHashMap<>();
         for (final Method m : allMethods) {
-            if (m.getParameterCount() != 0) {
+            if (m.getParameterCount() != 0 || !m.isAccessible()) {
+                continue;
+            }
+            final Object expectedValue;
+            try {
+                expectedValue = m.invoke(credential);
+            } catch (IllegalAccessException e) {
                 continue;
             }
-            final Object expectedValue = m.invoke(credential);
             expectedResults.put(m, expectedValue);
         }
         final String expectedId = credential.getId();