Disable test for JAR overwriting on windows

Adapted from scala commit 3d7e5c3888e0c0ce46315ea6918fd03b22f1fcb4 by
Jason Zaugg in scala/scala#6077

Author: allanrenucci

compiler/test/dotty/tools/dotc/classpath/ZipAndJarFileLookupFactoryTest.scala

@@ -11,6 +11,8 @@ import dotty.tools.io.AbstractFile
 
 class ZipAndJarFileLookupFactoryTest {
   @Test def cacheInvalidation(): Unit = {
+    if (scala.util.Properties.isWin) return // can't overwrite an open file on windows.
+
     val f = Files.createTempFile("test-", ".jar")
     Files.delete(f)