[SR-8922] repl trap when printing Foundation.DateFormatter

[kevints]

Previous ID	SR-8922
Radar	None
Original Reporter	@kevints
Type	Bug

Environment

Swift 4.2-RELEASE
Ubuntu 14.04

Additional Detail from JIRA

Votes	0
Component/s	LLDB for Swift
Labels	Bug, Linux
Assignee	None
Priority	Medium

md5: 76cd071fc69695a5b9a342462e93a6a0

Issue Description:

Crash in swift`apinotes_main

root@c33411474ab4:/code# ./releases/swift-4.2-RELEASE-ubuntu14.04/usr/bin/swift
Welcome to Swift version 4.2 (swift-4.2-RELEASE). Type :help for assistance.
  1> import Foundation
  2> let df = DateFormatter()
df: Foundation.DateFormatter = {
  Foundation.Formatter = {
    Foundation.NSObject = {}
  }
  __cfObject =Segmentation fault (core dumped)

Backtrace:

./releases/swift-4.2-RELEASE-ubuntu14.04/usr/bin/lldb ./releases/swift-4.2-RELEASE-ubuntu14.04/usr/bin/swift -c core
(lldb) target create "./releases/swift-4.2-RELEASE-ubuntu14.04/usr/bin/swift" --core "core"
Core file '/code/core' (x86_64) was loaded.
(lldb) bt
* thread #​1, name = 'repl_swift', stop reason = signal SIGTRAP
  * frame #&#8203;0: 0x00000000004006c1 swift`apinotes_main(llvm::ArrayRef<char const*>)
    frame #&#8203;1: 0x00000000004006e7 swift`apinotes_main(llvm::ArrayRef<char const*>) + 38