The last instruction did not unwind correctly. Also add .type and .size
annotations so that errors show up properly.

Change-Id: Id18e12b4ed51bdabb90bd5ac66631fd989649eec
Reviewed-on: https://boringssl-review.googlesource.com/c/34190
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>