Restore async logger condition in Log4j2 tests

The async logger condition was removed in the previous commit which
caused testAsyncLogger to fail. AsyncLogger doesn't capture source
location attributes by default in non-latest dependency tests, so
this check is needed to return empty code location attributes in
that case.

Author: trask

instrumentation/log4j/log4j-appender-2.17/testing/src/main/java/io/opentelemetry/instrumentation/log4j/appender/v2_17/AbstractLog4j2Test.java

@@ -266,11 +266,17 @@ protected static void performLogging(
   }
 
   protected static List<AttributeAssertion> addCodeLocationAttributes(String methodName) {
-    // Code attributes are enabled in both javaagent and library test configurations
-    List<AttributeAssertion> assertions = new ArrayList<>();
-    assertions.addAll(codeFunctionAssertions(AbstractLog4j2Test.class, methodName));
-    assertions.addAll(codeFileAndLineAssertions("AbstractLog4j2Test.java"));
-    return assertions;
+    String selector = System.getProperty("Log4j2.contextSelector");
+    boolean async = selector != null && selector.endsWith("AsyncLoggerContextSelector");
+    if (async && !Boolean.getBoolean("testLatestDeps")) {
+      // source info is not available by default when async logger is used in non latest dep tests
+      return new ArrayList<>();
+    }
+
+    List<AttributeAssertion> result = new ArrayList<>();
+    result.addAll(codeFunctionAssertions(AbstractLog4j2Test.class, methodName));
+    result.addAll(codeFileAndLineAssertions("AbstractLog4j2Test.java"));
+    return result;
   }
 
   @FunctionalInterface