Revert "Merge pull request #76406 from glessard/rdar96837923-span"

This reverts commit 20b85ed, reversing
changes made to 0d7054b.

The changes to the `_isPOD()` functions aren’t reverted.

Author: glessard

stdlib/public/core/CMakeLists.txt

@@ -154,8 +154,6 @@ split_embedded_sources(
   EMBEDDED Slice.swift
   EMBEDDED SmallString.swift
   EMBEDDED Sort.swift
-  EMBEDDED Span/RawSpan.swift
-  EMBEDDED Span/Span.swift
   EMBEDDED StaticString.swift
   EMBEDDED StaticPrint.swift
   EMBEDDED Stride.swift

stdlib/public/core/GroupInfo.json

@@ -198,10 +198,6 @@
     "UnsafeBufferPointerSlice.swift",
     "UnsafeRawBufferPointer.swift"
   ],
-  "Span": [
-    "RawSpan.swift",
-    "Span.swift"
-  ],
   "Protocols": [
     "CompilerProtocols.swift",
     "ShadowProtocols.swift"