Add elm-tools/parser-primitives to native whitelist

Will let anyone write faster parsing libraries. Kind of belongs in core, but the functions are so crazy that I do not want people thinking they should ever use them under normal circumstances.

Author: evancz

native-whitelist.json

@@ -15,6 +15,7 @@
     "elm-lang/virtual-dom",
     "elm-lang/websocket",
     "elm-lang/window",
+    "elm-tools/parser-primitives",
     "eeue56/elm-html-test",
     "evancz/elm-graphics",
     "evancz/elm-markdown",