[CoreML][iOS/MacOS] Add the CoreML executor (#64522)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64522
The `PTMCoreMLExecutor` serves as a bridge between the delegate APIs and Core ML runtime.
ghstack-source-id: 138324217
allow-large-files
Test Plan:
iOS:
Run the CoreML tests in the playground app
MacOS:
```
buck test pp-macos
PASS 633ms 1 Passed 0 Skipped 0 Failed CoreMLTests
```
{F657776101}
Reviewed By: raziel, iseeyuan
Differential Revision: D30594042
fbshipit-source-id: a42a5307a24c2f364333829f3a84f7b9a51e1b3e
