Give more memory to surefire when running the full test suite

There are so many tests now that their metadata takes up a considerable amount of memory.

Dockerfile

@@ -33,4 +33,7 @@ RUN mvn dependency:go-offline surefire:test checkstyle:check -ntp
 
 # Copy over the project code and run our build
 COPY . .
+# Make sure Maven has enough memory to keep track of all the tests we run
+ENV MAVEN_OPTS="-Xmx3g -XX:+HeapDumpOnOutOfMemoryError"
+# Run tests
 CMD mvn verify -o -B -C -T1C -fae -nsu -npu

pom.xml

@@ -78,6 +78,7 @@
       -server
       -dsa -da -ea:io.netty...
       -XX:+HeapDumpOnOutOfMemoryError
+      -Xmx3g
       -Dio.netty.tryReflectionSetAccessible=true
       --add-opens java.base/java.nio=io.netty.common
     </argLine.common>

src/main/java/module-info.java

@@ -34,4 +34,4 @@ module netty.incubator.buffer {
             io.netty.buffer.api.memseg.SegmentMemoryManagers,
             io.netty.buffer.api.bytebuffer.ByteBufferMemoryManagers,
             io.netty.buffer.api.unsafe.UnsafeMemoryManagers;
-}
+}

src/test/java/io/netty/buffer/api/BufferTest.java

@@ -33,7 +33,6 @@ import java.nio.ReadOnlyBufferException;
 import java.text.ParseException;
 import java.time.Instant;
 import java.time.temporal.ChronoUnit;
-import java.time.temporal.TemporalUnit;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.LinkedList;
@@ -44,6 +43,7 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Function;
@@ -349,7 +349,14 @@ public class BufferTest {
 
     @BeforeAll
     static void startExecutor() throws IOException, ParseException {
-        executor = Executors.newSingleThreadExecutor();
+        executor = Executors.newSingleThreadExecutor(new ThreadFactory() {
+            @Override
+            public Thread newThread(Runnable r) {
+                Thread thread = Executors.defaultThreadFactory().newThread(r);
+                thread.setDaemon(true); // Do not prevent shut down of test runner.
+                return thread;
+            }
+        });
     }
 
     @AfterAll