improv: type alias handling in TypeInfoCache

[bokken]

populate the "real" types into the map to avoid case conversions to
check for alternate representations.
populate new mappings to optimize future use

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[davecramer]

Much prefer using CAPITAL letters for static identifiers

[bmistry13]

Please check for input alias. If it is NPE it will result in NPE.

[bmistry13]

You may want to add null as testcase.