Remove unused diagnostics Compiler#OPTIMIZE_LOOP_ERROR and Compiler#MOTION_ITERATIONS_ERROR.
Remove unused diagnostics Compiler#OPTIMIZE_LOOP_ERROR and Compiler#MOTION_ITERATIONS_ERROR.

PiperOrigin-RevId: 445532647

monetate/closure-compiler,nawawi/closure-compiler,monetate/closure-compiler,monetate/closure-compiler,ChadKillingsworth/closure-compiler,ChadKillingsworth/closure-compiler,nawawi/closure-compiler,ChadKillingsworth/closure-compiler,google/closure-compiler,nawawi/closure-compiler,google/closure-compiler,ChadKillingsworth/closure-compiler,monetate/closure-compiler,nawawi/closure-compiler,google/closure-compiler,google/closure-compiler