Since Jan's recent addition of the lastLookups_ cache in StringToAtomCache, part of the string atomization workflow is easier to write as masm and not so much code to worry about bloating things. This made me interested in revisiting whether we should try to inline GetNativeDataPropertyByValuePure, as previously I had concluded that we missed too often due to not having atom strings. Running my prototype of this through try I see pretty green results for React-Redux-TodoMVC and Elm-TodoMVC. Quite a bit of this seems to overlap with bug 1799025, but I think they are both worth doing anyway.

This changes our JIT megamorphic cache accessors to hit more often by allowing
them to look up strings in the first level of StringToAtomCache's cache.

This also extracts the common bit of code from the HasProp case as well as the
common code from the GetProp case in order to merge them together for the
GetElem case.

Depends on D165427

https://hg.mozilla.org/mozilla-central/rev/3c3f18541794
https://hg.mozilla.org/mozilla-central/rev/b17b04940a8f

This saw something like a 3% win on React-Redux-TodoMVC and similar on React-TodoMVC and Elm-TodoMVC

FWIW, also gave a 11% win on AWFY-Sunspider-string-fasta : https://treeherder.mozilla.org/perfherder/graphs?highlightAlerts=1&highlightChangelogData=1&highlightCommonAlerts=0&selected=3906902,1622585925&series=mozilla-central,3735763,1,13&series=mozilla-central,3735763,1,13&series=autoland,3906902,1,13&timerange=5184000&zoom=1672646821296,1672927253902,6.13886547683267,10.327579970191508