Merge pull request #1680 from practicalswift/swiftc-28271-swift-archetypebuilder-getallarchetypes

[swiftc] Add test case for crash triggered in swift::ArchetypeBuilder::getAllArchetypes()

Author: tkremenek

validation-test/compiler_crashers/28271-swift-archetypebuilder-getallarchetypes.swift

@@ -0,0 +1,9 @@
+// This source file is part of the Swift.org open source project
+// See http://swift.org/LICENSE.txt for license information
+
+// RUN: not --crash %target-swift-frontend %s -parse
+// REQUIRES: asserts
+func b{{
+protocol P{func b
+func b<T where T=e
+typealias e