Rename the source file to match the function name and thereby
also make room for a possible future even slightly faster
"non-safe" decompressor version.
Signed-off-by: Markus F.X.J. Oberhumer <markus@oberhumer.com>

(cherry picked from commit b6bec26c)
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>