Remove netty workaround (#13975)

Author: laurit

testing-common/src/main/java/io/opentelemetry/instrumentation/testing/InstrumentationTestRunner.java

@@ -45,16 +45,6 @@
  */
 public abstract class InstrumentationTestRunner {
 
-  static {
-    // In netty-4.1.121.Final unsafe usage is disabled by default on jdk24. This triggers using
-    // a different pooled buffer implementation which apparently breaks when initializing ssl. Here
-    // we switch to unpooled buffers to avoid that bug. We do this here because this code is
-    // executed early for both agent and library tests.
-    if (Double.parseDouble(System.getProperty("java.specification.version")) >= 24) {
-      System.setProperty("io.opentelemetry.testing.internal.io.netty.allocator.type", "unpooled");
-    }
-  }
-
   private final TestInstrumenters testInstrumenters;
   protected Map<String, MetricData> metrics = new HashMap<>();