Removed compatibility option LUA_COMPAT_GCPARAMS

The meaning of different GC parameters changed, so there is point in
supporting old values for them. The new code simply ignores the
parameters when changing the GC mode, so the incompatibility is small.

testes/gc.lua

@@ -504,7 +504,7 @@ end
 do
   collectgarbage()
   collectgarbage"stop"
-  collectgarbage("step", 0)   -- steps should not unblock the collector
+  collectgarbage("step")   -- steps should not unblock the collector
   local x = gcinfo()
   repeat
     for i=1,1000 do _ENV.a = {} end   -- no collection during the loop