Skip some tests under Windows that _sometimes_ fail there.

I had reported a failure post-submit on cl/538862954, and I just saw another one while testing cl/542572673.

RELNOTES=n/a
PiperOrigin-RevId: 542608139

Author: cpovirk

guava-tests/test/com/google/common/io/MoreFilesTest.java

@@ -262,6 +262,9 @@ public void testTouchTime() throws IOException {
   }
 
   public void testCreateParentDirectories_root() throws IOException {
+    if (isWindows()) {
+      return; // TODO: b/136041958 - *Sometimes* fails with "A:\: The device is not ready"
+    }
     Path root = root();
     assertNull(root.getParent());
     assertNull(root.toRealPath().getParent());
@@ -329,6 +332,9 @@ public void testCreateParentDirectories_nonDirectoryParentExists() throws IOExce
   }
 
   public void testCreateParentDirectories_symlinkParentExists() throws IOException {
+    if (isWindows()) {
+      return; // TODO: b/136041958 - *Sometimes* fails with FileAlreadyExistsException
+    }
     Path symlink = tempDir.resolve("linkToDir");
     Files.createSymbolicLink(symlink, root());
     Path file = symlink.resolve("foo");