Code Review - CR# 7030573 insufficient disk space for large file test

[Gary Adams]

The LargeFileAvailable regression test had intermittent failures
when there was not sufficient space available to create
a 7G temp file. This webrev presents a simple check to
see if the available usable space is less than 7G and
scales the test back accordingly.

The original bug report suggests that the test be switched
to use the current working directory rather than a temp
file. I think that could be the wrong choice for an embedded
system that might have the tests mounted from a remote
file system. In that scenario, using the local temp file
space provides a better solution for what this test is designed
to check.

   http://cr.openjdk.java.net/~gadams/7030573/