tests: delete temporary resize test files

tests: delete temporary resize test files

Since commit 5ad07acad if $TMP cannot hold large test filesystems
for resize testing the resize_test creates temporary test files
in the local working directory.  Since it overrides TMPFILE locally
the calling program does not delete the generated file correctly.

Delete the large $TMPFILE within resize_test if it passes, but leave
it for debugging if the test failed.

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>