Splat vnode tests must return negative error codes.

Splat vnode tests must return negative error codes.

I must have been in a hurry when I wrote the vnode regression tests
because the error code handling is not correct.  The Solaris vnode
API returns positive errno's, these need to be converted to negative
errno's for Linux before being passed back to user space.  Otherwise
the test hardness with report the failure but errno will not be set
with the correct error code.

Additionally tests 3, 4, 6, and 7 may fail in the test file already
exists.  To avoid false positives a user mode helper has added to
remove the test files in /tmp/ before running the actual test.