Fix leak in SubRunInitializer

Bug: oss-fuzz:47844
Change-Id: I5b44801bb11433bfa1bfb88f374f750051dc7eec
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/548397
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Herb Derby <herb@google.com>
1 file changed