Stack trace from one of the failures:

java.nio.file.FileSystemException: D:\\src\\jake\\jdk\\test\\jdk\\jigsaw\\tools\\jlink\\JTwork\\scratch\\jmods\\module.jmod: The process cannot access the file because it is being used by another process.

at sun.nio.fs.WindowsException.translateToIOException(java.base@9-internal/WindowsException.java:86)
at sun.nio.fs.WindowsException.rethrowAsIOException(java.base@9-internal/WindowsException.java:97)
at sun.nio.fs.WindowsException.rethrowAsIOException(java.base@9-internal/WindowsException.java:102)
at sun.nio.fs.WindowsFileSystemProvider.implDelete(java.base@9-internal/WindowsFileSystemProvider.java:270)
at sun.nio.fs.AbstractFileSystemProvider.delete(java.base@9-internal/AbstractFileSystemProvider.java:103)
at java.nio.file.Files.delete(java.base@9-internal/Files.java:1127)
at JLinkNegativeTest$1.visitFile(JLinkNegativeTest.java:81)
at JLinkNegativeTest$1.visitFile(JLinkNegativeTest.java:78)
at java.nio.file.Files.walkFileTree(java.base@9-internal/Files.java:2676)
at java.nio.file.Files.walkFileTree(java.base@9-internal/Files.java:2748)
at JLinkNegativeTest.deleteDirectory(JLinkNegativeTest.java:78)
at JLinkNegativeTest.testSectionsAreFiles(JLinkNegativeTest.java:267)
at sun.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-internal/Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(java.base@9-internal/NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-internal/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-internal/Method.java:531)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:714)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
at org.testng.TestRunner.privateRun(TestRunner.java:767)
at org.testng.TestRunner.run(TestRunner.java:617)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:329)
at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291)
at org.testng.SuiteRunner.run(SuiteRunner.java:240)
at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
at org.testng.TestNG.run(TestNG.java:1057)
at com.sun.javatest.regtest.TestNGAction$TestNGRunner.main(TestNGAction.java:220)
at com.sun.javatest.regtest.TestNGAction$TestNGRunner.main(TestNGAction.java:184)
at sun.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-internal/Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(java.base@9-internal/NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-internal/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-internal/Method.java:531)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:110)
at java.lang.Thread.run(java.base@9-internal/Thread.java:804)