Revert "libfoundation: Correct MCRecordHash logic."

This reverts commit 48cace92fca6d4263806d4f0d1700147488545cc.
libfoundation: Correct MCRecordHash logic.
    
Two record values are only the same if they have the same named
typeinfo, and the same values in each field.
    
This makes it less likely that __MCRecordHash(a) == __MCRecordHash(b)
when __MCRecordIsEqualTo(a,b) == false.

This is a corrected version of commit 48cace92fca6.
Merge pull request #1542 from peter-b/develop

libfoundation: MCRecord fixes.