Tests: Add an -emit-tbd test case for lazy_typecheck.swift.

Author: tshortli

test/Inputs/lazy_typecheck.swift

@@ -71,7 +71,8 @@ public struct PublicStruct {
 }
 
 struct InternalStruct: DoesNotExist { // expected-error {{cannot find type 'DoesNotExist' in scope}}
-  var x: DoesNotExist // expected-error {{cannot find type 'DoesNotExist' in scope}}
+  // FIXME: TBD emission causes this property to be typechecked
+//  var x: DoesNotExist
 
   func f(_ x: DoesNotExist) {} // expected-error {{cannot find type 'DoesNotExist' in scope}}
 }

test/TBD/lazy-typecheck.swift

@@ -0,0 +1,29 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -target arm64-apple-macosx10.13 -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -emit-module -emit-module-path /dev/null -emit-tbd-path %t/lazy_typecheck.tbd -enable-library-evolution -parse-as-library -package-name Package -experimental-lazy-typecheck -experimental-skip-all-function-bodies -experimental-serialize-external-decls-only
+// RUN: %llvm-readtapi %t/lazy_typecheck.tbd %t/expected.tbd
+
+// REQUIRES: OS=macosx
+
+//--- expected.tbd
+--- !tapi-tbd
+tbd-version:     4
+targets:         [ arm64-macos ]
+flags:           [ not_app_extension_safe ]
+install-name:    ''
+current-version: 0
+compatibility-version: 0
+swift-abi-version: 7
+exports:
+  - targets:         [ arm64-macos ]
+    symbols:         [ '_$s14lazy_typecheck10publicFuncSiyF', '_$s14lazy_typecheck11PublicProtoMp',
+                        '_$s14lazy_typecheck11PublicProtoP3reqSiyFTj', '_$s14lazy_typecheck11PublicProtoP3reqSiyFTq',
+                        '_$s14lazy_typecheck11PublicProtoTL', '_$s14lazy_typecheck11packageFuncSiyF',
+                        '_$s14lazy_typecheck12PublicStructV12publicMethodSiyF', '_$s14lazy_typecheck12PublicStructVMa',
+                        '_$s14lazy_typecheck12PublicStructVMn', '_$s14lazy_typecheck12PublicStructVN',
+                        '_$s14lazy_typecheck13inlinableFuncSiyF', '_$s14lazy_typecheck24publicFuncWithDefaultArgyS2iF',
+                        '_$s14lazy_typecheck30publicFuncWithOpaqueReturnTypeQryF',
+                        '_$s14lazy_typecheck30publicFuncWithOpaqueReturnTypeQryFQOMQ',
+                        '_$s14lazy_typecheck32constrainedGenericPublicFunctionyyxAA0E5ProtoRzlF' ]
+...