[stdlib] remove incorrect uses of pointer conversion

Author: glessard

stdlib/private/StdlibUnittest/StdlibUnittest.swift

@@ -2182,9 +2182,10 @@ func _getSystemVersionPlistProperty(_ propertyName: String) -> String? {
 func _getSystemVersionPlistProperty(_ propertyName: String) -> String? {
   var count = 0
   sysctlbyname("kern.osproductversion", nil, &count, nil, 0)
-  var s = [CChar](repeating: 0, count: count)
-  sysctlbyname("kern.osproductversion", &s, &count, nil, 0)
-  return String(cString: &s)
+  return withUnsafeTemporaryAllocation(of: CChar.self, capacity: count) {
+    sysctlbyname("kern.osproductversion", $0.baseAddress, &count, nil, 0)
+    return String(cString: $0.baseAddress!)
+  }
 }
 #endif
 #endif

stdlib/private/SwiftReflectionTest/SwiftReflectionTest.swift

@@ -373,25 +373,25 @@ internal func reflect(instanceAddress: UInt,
                       shouldUnwrapClassExistential: Bool = false) {
   while let command = readLine(strippingNewline: true) {
     switch command {
-    case String(validatingUTF8: RequestInstanceKind)!:
+    case RequestInstanceKind:
       sendValue(kind.rawValue)
-    case String(validatingUTF8: RequestShouldUnwrapClassExistential)!:
+    case RequestShouldUnwrapClassExistential:
       sendValue(shouldUnwrapClassExistential)
-    case String(validatingUTF8: RequestInstanceAddress)!:
+    case RequestInstanceAddress:
       sendValue(instanceAddress)
-    case String(validatingUTF8: RequestReflectionInfos)!:
+    case RequestReflectionInfos:
       sendReflectionInfos()
-    case String(validatingUTF8: RequestImages)!:
+    case RequestImages:
       sendImages()
-    case String(validatingUTF8: RequestReadBytes)!:
+    case RequestReadBytes:
       sendBytes()
-    case String(validatingUTF8: RequestSymbolAddress)!:
+    case RequestSymbolAddress:
       sendSymbolAddress()
-    case String(validatingUTF8: RequestStringLength)!:
+    case RequestStringLength:
       sendStringLength()
-    case String(validatingUTF8: RequestPointerSize)!:
+    case RequestPointerSize:
       sendPointerSize()
-    case String(validatingUTF8: RequestDone)!:
+    case RequestDone:
       return
     default:
       fatalError("Unknown request received: '\(Array(command.utf8))'!")