build: fix debug flags for LuaJIT assertions

This patch fixes inaccuracy in Tarantool build configuration introduced
by commit 07c83aab ('build: adjust
LuaJIT build system'). That patch sets LUAJIT_USE_ASSERT and
LUAJIT_USE_APICHECK options for Debug build instead of LUA_USE_ASSERT
and LUA_USE_APICHECK respectively. This patch fixes these typos.

Follows up #4862

Reviewed-by: Sergey Ostanevich <sergos@tarantool.org>
Reviewed-by: Igor Munkin <imun@tarantool.org>
Signed-off-by: Igor Munkin <imun@tarantool.org>