[stdlib] use the internal precondition calls

Author: glessard

stdlib/public/core/UnsafeBufferPointer.swift.gyb

@@ -1018,7 +1018,7 @@ extension Unsafe${Mutable}BufferPointer {
   @inlinable
   @_alwaysEmitIntoClient
   public func initializeElement(at index: Index, to value: Element) {
-    precondition(startIndex <= index && index < endIndex)
+    _debugPrecondition(startIndex <= index && index < endIndex)
     let p = baseAddress._unsafelyUnwrappedUnchecked.advanced(by: index)
     p.initialize(to: value)
   }
@@ -1036,7 +1036,7 @@ extension Unsafe${Mutable}BufferPointer {
   @inlinable
   @_alwaysEmitIntoClient
   public func moveElement(from index: Index) -> Element {
-    precondition(startIndex <= index && index < endIndex)
+    _debugPrecondition(startIndex <= index && index < endIndex)
     return baseAddress._unsafelyUnwrappedUnchecked.advanced(by: index).move()
   }
 
@@ -1051,7 +1051,7 @@ extension Unsafe${Mutable}BufferPointer {
   @inlinable
   @_alwaysEmitIntoClient
   public func deinitializeElement(at index: Index) {
-    precondition(startIndex <= index && index < endIndex)
+    _debugPrecondition(startIndex <= index && index < endIndex)
     let p = baseAddress._unsafelyUnwrappedUnchecked.advanced(by: index)
     p.deinitialize(count: 1)
   }

stdlib/public/core/UnsafeBufferPointerSlice.swift

@@ -1118,7 +1118,7 @@ extension Slice {
       var slice = UnsafeMutableBufferPointer(start: start, count: count)
       let (b,c) = (slice.baseAddress, slice.count)
       defer {
-        precondition(
+        _precondition(
           slice.baseAddress == b && slice.count == c,
           "Slice.withContiguousMutableStorageIfAvailable: " +
           "replacing the buffer is not allowed")