luajit: bump new a new version

List of changes
     - fold: keep type of emitted CONV in sync with its mode
     - test: adjust the test name related to PAIRSMM flag

(cherry picked from commit e12930d0)

luajit @ c9588f51

-Subproject commit d4e985a159639e8ad8a83b792e1883a294761c05
+Subproject commit c9588f51301844d11a2a9dfa9070e437961c9787