Exclude failing Java test.

It fails with runc as well, likely the image certificate expired.

PiperOrigin-RevId: 797412243

Author: konstantin-s-bogom

test/runtimes/exclude/java21.csv

@@ -126,3 +126,4 @@ tools/jpackage/share/jdk/jpackage/tests/MultipleJarAppTest.java,,Broken test
 tools/jpackage/share/jdk/jpackage/tests/NoMPathRuntimeTest.java,,Broken test
 tools/launcher/BigJar.java,b/111611473,Broken test
 tools/launcher/JliLaunchTest.java,,Broken test
+java/net/CookieHandler/B6644726.java,,Broken test