Enable ProcessManagerTest#testCloseNonStandardFds

Instead of using the /proc/version which is no longer accessible for CTS
testing, to create a new file descriptor for the test, a temporary file
is used.

Bug: 29495646
Test: cts-tradefed run cts -m CtsLibcoreTestCases -t \
       org.apache.harmony.tests.java.lang.ProcessManagerTest#testCloseNonStandardFds

Change-Id: Ib45ee6ab7b0c8972dae6386a0b41ac9da5f6086f