[clang] [Clang][Sema] placement new initializes typedef array with correct size (PR #83124)

[Erich Keane via cfe-commits]

erichkeane wrote:

I definitely agree with both of Shafik's comments!  

The fix itself concerns me, the logic in the block that is having its condition inverted is specifically made for 'if no array size was specified' (see comment), so that makes me think this is an incorrect patch.  It doesn't seem to follow the suggestion given in the original bug either.

https://github.com/llvm/llvm-project/pull/83124