[FLINK-24995][tests] Migrate tests to ConsoleReporter#finish

'ConsoleReporter#finish' behaves just like '#printSummary', but is also supported in later versions.
Additionally, we now fail the test if the compiler reported any warnings/errors, as without it the summary business didn't provide a benefit in the first place.

flink-scala/src/test/scala/org/apache/flink/api/scala/typeutils/EnumValueSerializerCompatibilityTest.scala

@@ -189,6 +189,9 @@ object EnumValueSerializerCompatibilityTest {
 
     run.compile(List(file.getAbsolutePath))
 
-    reporter.printSummary()
+    if (reporter.hasWarnings || reporter.hasErrors) {
+      reporter.finish()
+      fail("Scala compiler reported warnings or errors")
+    }
   }
 }