Have the default JDWP sync connection port be chosen by the OS.

When the JDWP port number for the sync connection is not set
explicitly (by assigning a value to the the
jpda.settings.syncPort runtime property), let the OS decide
which port to open.

(cherry picked from commit 425673da79426d66c1ea05029f295b63d0e8a3c6)

Bug: 28869570
Change-Id: I265429249268da5df38aa112886b64eef7860221
1 file changed