Add test case for <rdar://problem/63191951>

Author: slavapestov

test/DebugInfo/Inputs/curry_thunk_other.swift

@@ -0,0 +1,7 @@
+public struct HTTPMethod {
+  public let rawValue: String
+
+  public init(rawValue: String) {
+    self.rawValue = rawValue
+  }
+}

test/DebugInfo/curry_thunk.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-frontend -primary-file %s %S/Inputs/curry_thunk_other.swift -emit-ir -g -o - | %FileCheck %s
+
+public func testCurryThunk() -> [HTTPMethod] {
+  return ["asdf"].map(HTTPMethod.init)
+}
+
+// CHECK: [[FILE:![0-9]+]] = !DIFile(filename: "{{.*}}/curry_thunk.swift", directory: "{{.*}}")
+// CHECK: {{![0-9]+}} = !DILocalVariable(name: "rawValue", arg: 1, scope: {{![0-9]+}}, file: {{![0-9]+}}, type: {{![0-9]+}}, flags: DIFlagArtificial)