generic: more tests should clean up TESTDIR on success

I'm getting enospc errors on a 4GB test device after a while of
running. Part of the issue is that many tests can't or don't clean
up previous failed runs when they start or if the run to success.
Hence while we want to slowly age the test filesystem, we don't
really want that aging to unintentionally run the filesystem out of
space. To that end:

$ sudo du -s /mnt/test/* | sort -nr |head -10
1929160 /mnt/test/fsfile
512000  /mnt/test/247.8133
512000  /mnt/test/247.4713
512000  /mnt/test/247.4488
466752  /mnt/test/fstest.9850.2
40000   /mnt/test/resv
29804   /mnt/test/fsstress.12144.1
26208   /mnt/test/populate_root
26208   /mnt/test/mnt
23216   /mnt/test/fsstress.4491.1

We can see that there are a few tests that using most of the space.
These are often left behind due to kernel failures during tests or
reboots while tests are in progress, so make sure that they at least
clean up such mess the next time they run.

Test generic/247, xfs/020 (fsfile) and generic/074 (fstest.$$.n)
are the worst offenders, so just target these to being with.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

tests/xfs/020

@@ -37,7 +37,7 @@ _cleanup()
 {
     cd /
     rm -f $tmp.*
-    rm -f $TEST_DIR/fsfile
+    rm -f $fsfile
 }
 
 # get standard environment, filters and checks
@@ -51,8 +51,11 @@ _require_test
 
 echo "Silence is golden"
 
-$MKFS_PROG -t xfs -d size=60t,file,name=$TEST_DIR/fsfile >/dev/null
-$XFS_REPAIR_PROG -o ag_stride=32 -t 1 $TEST_DIR/fsfile >/dev/null 2>&1
+fsfile=$TEST_DIR/fsfile.$seq
+rm -f $fsfile
+
+$MKFS_PROG -t xfs -d size=60t,file,name=$fsfile >/dev/null
+$XFS_REPAIR_PROG -o ag_stride=32 -t 1 $fsfile >/dev/null 2>&1
 
 status=$?
 exit