CFPropertyList: fix CFPropertyListCreateDeepCopy of mutable containers

[DTW-Thalion]

Summary

CFPropertyListCreateDeepCopy could not deep-copy a mutable array or
dictionary, for two reasons:

1. Type IDs never initialised on this path. CFPropertyListInitTypeIDs
   (which lazily fills _kCFArrayTypeID, _kCFDictionaryTypeID, …) was only
   called from the validation code. On a standalone CFPropertyListCreateDeepCopy
   call, every CFGetTypeID(...) == _kCF*TypeID comparison saw 0, no branch
   matched, and the function returned NULL.

2. Copy applied over the empty destination. Once the type IDs are
   initialised, the mutable array and dictionary branches applied their copy
   function over the freshly-created (empty) destination container instead of
   the source plist:

   array = CFArrayCreateMutable (alloc, cnt, ...);   /* empty */
   CFArrayApplyFunction (array, range, CFArrayCopyFunction, &ctx);  /* <- wrong */

   so the result came back empty (and iterating the empty array over
   range (0, cnt) was itself out of range).

Fix

Call CFPropertyListInitTypeIDs() at the top, and apply the copy functions
over the source plist.

Test

Tests/CFPropertyList/deepcopy.m: deep-copying a mutable array and a mutable
dictionary preserves their elements.