Patch java-junit to handle missing time field

Normally a <testsuites> element has a time field. In some JUnit implementations this field is missing. This issue was found in junit XML created in matlab.

At the moment I don't plan to explicitly support matlab - that would require to add more tests and documentation. However this patch should make it work with the existing java-junit parser.

src/parsers/java-junit/java-junit-parser.ts

@@ -70,7 +70,8 @@ export class JavaJunitParser implements TestParser {
             return sr
           })
 
-    const time = parseFloat(junit.testsuites.$.time) * 1000
+    const seconds = parseFloat(junit.testsuites.$?.time)
+    const time = isNaN(seconds) ? undefined : seconds * 1000
     return new TestRunResult(filePath, suites, time)
   }