test: add a mock Swift framework into the ABI checker test suite

Author: nkcsgexi

test/api-digester/Inputs/mock-sdk-baseline.sdk/System/Library/Frameworks/SwiftFoo.framework/Modules/SwiftFoo.swiftmodule/x86_64-apple-macos.swiftinterface

@@ -0,0 +1,7 @@
+// swift-interface-format-version: 1.0
+// swift-tools-version: Apple Swift version 5.1 (swiftlang-1100.0.38 clang-1100.0.20.14)
+// swift-module-flags: -target x86_64-apple-macos10.14 -enable-objc-interop -enable-library-evolution -swift-version 5 -enforce-exclusivity=checked -O -module-name SwiftFoo
+import Swift
+public class RemovedClass {
+  @objc deinit
+}

test/api-digester/Inputs/mock-sdk-modules.txt

@@ -1 +1,2 @@
-Foo
+Foo
+SwiftFoo

test/api-digester/Inputs/mock-sdk.sdk/System/Library/Frameworks/SwiftFoo.framework/Modules/SwiftFoo.swiftmodule/x86_64-apple-macos.swiftinterface

@@ -0,0 +1,7 @@
+// swift-interface-format-version: 1.0
+// swift-tools-version: Apple Swift version 5.1 (swiftlang-1100.0.38 clang-1100.0.20.14)
+// swift-module-flags: -target x86_64-apple-macos10.14 -enable-objc-interop -enable-library-evolution -swift-version 5 -enforce-exclusivity=checked -O -module-name SwiftFoo
+import Swift
+public class AddedClass {
+  @objc deinit
+}

test/api-digester/Outputs/mock-sdk-api.txt

@@ -1 +1,2 @@
 Foo(Foo.h): Func removedFunction() has been removed
+SwiftFoo: Class RemovedClass has been removed

test/api-digester/compare-two-sdks.swift

@@ -1,9 +1,11 @@
+// REQUIRES: OS=macosx
+
 // RUN: %empty-directory(%t.mod1)
 // RUN: %empty-directory(%t.mod2)
 // RUN: %empty-directory(%t.sdk)
 // RUN: %empty-directory(%t.module-cache)
 
-// RUN: %api-digester -diagnose-sdk -print-module -module-list-file %S/Inputs/mock-sdk-modules.txt -sdk %S/Inputs/mock-sdk.sdk -bsdk %S/Inputs/mock-sdk-baseline.sdk -module-cache-path %t.module-cache -o %t.result 
+// RUN: %api-digester -diagnose-sdk -print-module -module-list-file %S/Inputs/mock-sdk-modules.txt -sdk %S/Inputs/mock-sdk.sdk -bsdk %S/Inputs/mock-sdk-baseline.sdk -module-cache-path %t.module-cache -o %t.result -abort-on-module-fail -target x86_64-apple-macos10.14
 
 // RUN: %clang -E -P -x c %S/Outputs/mock-sdk-api.txt -o - | sed '/^\s*$/d' > %t.expected
 // RUN: %clang -E -P -x c %t.result -o - | sed '/^\s*$/d' > %t.result.tmp