Merge remote-tracking branch 'origin/swift-3.1-branch' into stable
* origin/swift-3.1-branch:
Revert "[analyzer] Re-apply r283093 "Add extra notes to ObjCDeallocChecker""
[analyzer] DeallocChecker: Don't warn about directly-set IBOutlet ivars on macOS
[analyzer] Fix build error after r283660 - remove constexpr strings.
[analyzer] Re-apply r283094 "Improve CloneChecker diagnostics"
[analyzer] Re-apply r283093 "Add extra notes to ObjCDeallocChecker"
[analyzer] Re-apply r283092, attempt no.4, chunk no.4 (last)
[analyzer] Re-apply r283092, attempt no.4, chunk no.3, fixup 1.
[analyzer] Re-apply r283092, attempt no.4, chunk no.3.
[analyzer] Re-apply r283092, attempt no.4, chunk no.2.
[analyzer] Re-apply r283092, attempt no.4, a small chunk.