Enable libcore.java.io.FileInputStream#testReadProcVersion

The test was written for b/26117827 to check if available works
correctly for files which are not supported by ioctl. As /proc/version
is no longer accessible by CTS tests, the test now uses /dev/zero
instead. The name of the test has also changed to better reflect its
purpose.

Bug: 29495646
Test: cts-tradefed run cts -m CtsLibcoreTestCases -t \
      libcore.java.io.FileInputStreamTest#test_available_on_nonIOCTL_supported_file

Change-Id: Iad827eb2377168029a7333b0db279042bd2cdaa0