Fix CmdModifierTest#testMemoryLimitModified in cgroup2 environment.

The `testMemoryLimitModified` was failing in cgroup2 environment because of the missing
`/sys/fs/cgroup/memory/memory.limit_in_bytes` file.

In the cgroup2 environment a new file should be checked instead -- `/sys/fs/cgroup/memory.max`.

This commit intrdocues changes to `cat` both files:

1. `/sys/fs/cgroup/memory/memory.limit_in_bytes` from the first version of cgroup
2. `/sys/fs/cgroup/memory.max` from the second

Similar issues:

1. oracle/docker-images#1939
2. apify/crawlee#693

docs/examples/junit4/generic/src/test/java/generic/CmdModifierTest.java

@@ -39,7 +39,11 @@ public void testHostnameModified() throws IOException, InterruptedException {
 
     @Test
     public void testMemoryLimitModified() throws IOException, InterruptedException {
-        final Container.ExecResult execResult = memoryLimitedRedis.execInContainer("cat", "/sys/fs/cgroup/memory/memory.limit_in_bytes");
+        final Container.ExecResult execResult = memoryLimitedRedis.execInContainer(
+            "cat",
+            "/sys/fs/cgroup/memory/memory.limit_in_bytes",
+            "/sys/fs/cgroup/memory.max"
+        );
         assertEquals(String.valueOf(memoryInBytes), execResult.getStdout().trim());
     }
 }