Initialize sun.nio.ch.Iocp at runtime on Windows with JDK 11

[gwenneg]

This PR fixes the following error from #7269:

Error: com.oracle.graal.pointsto.constraints.UnsupportedFeatureException: No instances of sun.nio.ch.Iocp are allowed in the image heap as this class should be initialized at image runtime. Object has been initialized without the native-image initialization instrumentation and the stack trace can't be tracked.
Trace:
        at parsing sun.nio.ch.WindowsAsynchronousFileChannelImpl.open(WindowsAsynchronousFileChannelImpl.java:105)
Call path from entry point to sun.nio.ch.WindowsAsynchronousFileChannelImpl.open(FileDescriptor, boolean, boolean, ThreadPool):
        at sun.nio.ch.WindowsAsynchronousFileChannelImpl.open(WindowsAsynchronousFileChannelImpl.java:104)
        at sun.nio.fs.WindowsChannelFactory.newAsynchronousFileChannel(WindowsChannelFactory.java:215)
        at sun.nio.fs.WindowsFileSystemProvider.newAsynchronousFileChannel(WindowsFileSystemProvider.java:145)
        at java.nio.channels.AsynchronousFileChannel.open(AsynchronousFileChannel.java:253)
        at io.vertx.core.file.impl.AsyncFileImpl.<init>(AsyncFileImpl.java:97)
        at io.vertx.core.file.impl.FileSystemImpl.doOpen(FileSystemImpl.java:903)
        at io.vertx.core.file.impl.FileSystemImpl$18.perform(FileSystemImpl.java:897)
        at io.vertx.core.file.impl.FileSystemImpl$18.perform(FileSystemImpl.java:894)
        at io.vertx.core.file.impl.FileSystemImpl$BlockingAction.handle(FileSystemImpl.java:974)
        at io.vertx.core.file.impl.FileSystemImpl$BlockingAction.handle(FileSystemImpl.java:955)
        at io.vertx.core.impl.ContextImpl.lambda$executeBlocking$2(ContextImpl.java:316)
        at io.vertx.core.impl.ContextImpl$$Lambda$771/0x00000007c1b7e840.run(Unknown Source)
        at com.oracle.svm.core.jdk.RuntimeSupport.executeHooks(RuntimeSupport.java:144)
        at com.oracle.svm.core.jdk.RuntimeSupport.executeStartupHooks(RuntimeSupport.java:89)
        at com.oracle.svm.core.JavaMainWrapper.runCore(JavaMainWrapper.java:143)
        at com.oracle.svm.core.JavaMainWrapper.run(JavaMainWrapper.java:186)
        at com.oracle.svm.core.code.IsolateEnterStub.JavaMainWrapper_run_5087f5482cc9a6abc971913ece43acb471d2631b(generated:0)

[gsmet]

Merged, thanks!