StdlibUnittest: Fix NSException catching (broken by SE-0054).

Previously, the callback for objc_setUncaughtExceptionHandler
took a parameter of type 'AnyObject!', which was implicitly
unwrapped at all uses inside the closure. When that became
'AnyObject?', we started getting an extra layer of Optional in
the printed output.

This reverts the tests to their pre-4d540c2a state.

Author: jrose-apple

stdlib/private/StdlibUnittest/StdlibUnittest.swift.gyb

@@ -627,14 +627,17 @@ func _childProcess() {
 
 #if _runtime(_ObjC)
   objc_setUncaughtExceptionHandler {
+    let exception: AnyObject = $0!
     var stderr = _Stderr()
-    let maybeNSException = unsafeBitCast($0, to:_StdlibUnittestNSException.self)
+    let maybeNSException =
+        unsafeBitCast(exception, to: _StdlibUnittestNSException.self)
     if let name = maybeNSException.name {
       print("*** [StdlibUnittest] Terminating due to uncaught exception " +
-        "\(name): \($0)",
+        "\(name): \(exception)",
         to: &stderr)
     } else {
-      print("*** [StdlibUnittest] Terminating due to uncaught exception: \($0)",
+      print("*** [StdlibUnittest] Terminating due to uncaught exception: " +
+        "\(exception)",
         to: &stderr)      
     }
   }

validation-test/StdlibUnittest/NSException.swift

@@ -21,8 +21,7 @@ TestSuiteCrashes.test("uncaught") {
   raiseNSException()
 }
 // CHECK-LABEL: stdout>>> uncaught
-// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception Trogdor: Optional(Burnination)
-// FIXME: listed reason above should be "Burnination", not "Optional(Burnination)"; may have to do with SE-0054
+// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception Trogdor: Burnination
 // CHECK: stderr>>> CRASHED: SIG
 // CHECK: the test crashed unexpectedly
 // CHECK: [     FAIL ] NSExceptionCrashes.uncaught
@@ -33,7 +32,7 @@ TestSuiteCrashes.test("crashesAsExpected") {
   raiseNSException()
 }
 // CHECK-LABEL: stdout>>> crashesAsExpected
-// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception Trogdor: Optional(Burnination)
+// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception Trogdor: Burnination
 // CHECK: stderr>>> OK: saw expected "crashed: sig
 // CHECK: [       OK ] NSExceptionCrashes.crashesAsExpected
 
@@ -46,7 +45,7 @@ TestSuiteCrashes.test("crashesWithMessage")
   raiseNSException()
 }
 // CHECK-LABEL: stdout>>> crashesWithMessage
-// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception Trogdor: Optional(Burnination)
+// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception Trogdor: Burnination
 // CHECK: stderr>>> OK: saw expected "crashed: sig
 // CHECK: [       OK ] NSExceptionCrashes.crashesWithMessage
 
@@ -57,7 +56,7 @@ TestSuiteCrashes.test("nonNSException")
   objc_exception_throw("countryside")
 }
 // CHECK-LABEL: stdout>>> nonNSException
-// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception: Optional(countryside)
+// CHECK: stderr>>> *** [StdlibUnittest] Terminating due to uncaught exception: countryside
 // CHECK: stderr>>> OK: saw expected "crashed: sig
 // CHECK: [       OK ] NSExceptionCrashes.nonNSException