[apex] Really fix ApexLexer logging

The fix introduced with #503 (fba00843bb)
was incomplete and didn't work:
* The logger uses the full class name insteand of simple name
* After we changed the log level of the logger, the logger
  could be garbage collected before ApexLexer retrieves it and
  thus the configuration could be lost

pmd-dist/src/test/java/net/sourceforge/pmd/it/AllRulesIT.java

@@ -42,5 +42,8 @@ public class AllRulesIT extends AbstractBinaryDistributionTest {
         result.assertNoError("Use of deprecated attribute");
         result.assertNoErrorInReport("Error while processing");
         result.assertNoErrorInReport("Error while parsing");
+
+        // See bug #2092: [apex] ApexLexer logs visible when Apex is the selected language upon starting the designer 
+        result.assertNoError("Deduped array ApexLexer");
     }
 }