[macos] EmptyFolderPackageTest.java failed "hdiutil: create failed - No child processes"

The following test failed in the JDK15 CI:

tools/jpackage/share/EmptyFolderPackageTest.java

Here's a snippet from the log file:

2020-06-22 21:26:17.203 copy-helper[93139:97325886] About to copy "/var/folders/jn/3j5zlmnj4zs5tlhls80bv42r000_dc/T/jdk.incubator.jpackage9865149966853880464/images/image-6826357834524952144".
2020-06-22 21:26:56.359 diskimages-helper[93089:97325321] -processKernelRequest: will sleep received
2020-06-22 21:27:25.602 diskimages-helper[93089:97325321] -processKernelRequest: will sleep received
2020-06-22 21:27:53.330 copy-helper[93139:97325886] Copy finished.
2020-06-22 21:28:24.370 hdiutil[93086:97331467] helper died
DIHLDiskImageCreate() returned 10
(null)
hdiutil: create: returning 10
hdiutil: create failed - No child processes
java.io.IOException: Command [/usr/bin/hdiutil, create, -verbose, -srcfolder, /var/folders/jn/3j5zlmnj4zs5tlhls80bv42r000_dc/T/jdk.incubator.jpackage9865149966853880464/images/image-6826357834524952144, -volname, EmptyFolderPackageTest, -ov, /var/folders/jn/3j5zlmnj4zs5tlhls80bv42r000_dc/T/jdk.incubator.jpackage9865149966853880464/images/EmptyFolderPackageTest-tmp.dmg, -fs, HFS+, -format, UDRW] exited with 1 code
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.Executor.executeExpectSuccess(Executor.java:75)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.IOUtils.exec(IOUtils.java:167)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.IOUtils.exec(IOUtils.java:135)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.MacDmgBundler.buildDMG(MacDmgBundler.java:325)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.MacDmgBundler.bundle(MacDmgBundler.java:91)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.MacDmgBundler.execute(MacDmgBundler.java:493)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.Arguments.generateBundle(Arguments.java:680)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.Arguments.processArguments(Arguments.java:549)
at jdk.incubator.jpackage/jdk.incubator.jpackage.main.Main.execute(Main.java:98)
at jdk.incubator.jpackage/jdk.incubator.jpackage.main.Main.main(Main.java:52)
jdk.incubator.jpackage.internal.PackagerException: java.io.IOException: Command [/usr/bin/hdiutil, create, -verbose, -srcfolder, /var/folders/jn/3j5zlmnj4zs5tlhls80bv42r000_dc/T/jdk.incubator.jpackage9865149966853880464/images/image-6826357834524952144, -volname, EmptyFolderPackageTest, -ov, /var/folders/jn/3j5zlmnj4zs5tlhls80bv42r000_dc/T/jdk.incubator.jpackage9865149966853880464/images/EmptyFolderPackageTest-tmp.dmg, -fs, HFS+, -format, UDRW] exited with 1 code
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.MacDmgBundler.bundle(MacDmgBundler.java:96)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.MacDmgBundler.execute(MacDmgBundler.java:493)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.Arguments.generateBundle(Arguments.java:680)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.Arguments.processArguments(Arguments.java:549)
at jdk.incubator.jpackage/jdk.incubator.jpackage.main.Main.execute(Main.java:98)
at jdk.incubator.jpackage/jdk.incubator.jpackage.main.Main.main(Main.java:52)
Caused by: java.io.IOException: Command [/usr/bin/hdiutil, create, -verbose, -srcfolder, /var/folders/jn/3j5zlmnj4zs5tlhls80bv42r000_dc/T/jdk.incubator.jpackage9865149966853880464/images/image-6826357834524952144, -volname, EmptyFolderPackageTest, -ov, /var/folders/jn/3j5zlmnj4zs5tlhls80bv42r000_dc/T/jdk.incubator.jpackage9865149966853880464/images/EmptyFolderPackageTest-tmp.dmg, -fs, HFS+, -format, UDRW] exited with 1 code
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.Executor.executeExpectSuccess(Executor.java:75)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.IOUtils.exec(IOUtils.java:167)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.IOUtils.exec(IOUtils.java:135)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.MacDmgBundler.buildDMG(MacDmgBundler.java:325)
at jdk.incubator.jpackage/jdk.incubator.jpackage.internal.MacDmgBundler.bundle(MacDmgBundler.java:91)
... 5 more
TRACE: exec: Done. Exit code: 1
ERROR: Expected [0]. Actual [1]: Check command [/mesos/work_dir/jib-master/install/jdk-15+29-1432/macosx-x64.jdk/jdk-15.jdk/Contents/Home/bin/jpackage --input ./input --dest ./output --name EmptyFolderPackageTest --type dmg --main-jar hello.jar --main-class Hello --verbose](14) exited with 0 code
[ FAILED ] EmptyFolderPackageTest; checks=30
----------System.err:(55/3900)----------


This is a Tier2 failure so I'm starting this bug as a P3.
This "hdiutil: create failed - No child processes" failure mode
is fairly recent (last few days to a week or so).