Modify test to work correctly on simulator

`simctl spawn` does not propagate exit codes through, so we need the test to exit using `exit(0)`, not `fatalError()`.

Author: beccadax

test/Interop/SwiftToCxx/functions/swift-functions-execution.cpp

@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend %S/swift-functions.swift -typecheck -module-name Functions -clang-header-expose-decls=all-public -emit-clang-header-path %t/functions.h
+// RUN: %target-swift-frontend %S/swift-functions.swift -typecheck -module-name Functions -clang-header-expose-decls=all-public -emit-clang-header-path %t/functions.h  -cxx-interoperability-mode=upcoming-swift
 
 // RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-functions-execution.o -g
 // RUN: %target-interop-build-swift %S/swift-functions.swift -o %t/swift-functions-execution -Xlinker %t/swift-functions-execution.o -module-name Functions -Xfrontend -entry-point-function-name -Xfrontend swiftMain -g
 
 // RUN: %target-codesign %t/swift-functions-execution
-// RUN: not --crash %target-run %t/swift-functions-execution 2>&1 | %FileCheck %s
+// RUN: %target-run %t/swift-functions-execution 2>&1 | %FileCheck %s
 
 // REQUIRES: executable_test
 
@@ -24,14 +24,11 @@ int main() {
   assert(Functions::passTwoIntReturnIntNoArgLabel(1, 2) == 42);
   assert(Functions::passTwoIntReturnInt(1, 2) == 3);
   assert(Functions::passTwoIntReturnIntNoArgLabelParamName(1, 4) == 5);
-
-  fflush(NULL); // before fatalError() call
-
   Functions::passVoidReturnNever();
-  return 0;
+  return 42;
 }
 
 // CHECK: passVoidReturnVoid
 // CHECK-NEXT: passIntReturnVoid -1
 // CHECK-NEXT: passTwoIntReturnIntNoArgLabel
-// CHECK-NEXT: Functions/swift-functions.swift:{{[0-9]+}}: Fatal error: passVoidReturnNever
+// CHECK-NEXT: passVoidReturnNever

test/Interop/SwiftToCxx/functions/swift-functions.swift

@@ -1,7 +1,9 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %s -typecheck -module-name Functions -clang-header-expose-decls=all-public -emit-clang-header-path %t/functions.h
+// RUN: %target-swift-frontend %s -typecheck -module-name Functions -clang-header-expose-decls=all-public -emit-clang-header-path %t/functions.h  -cxx-interoperability-mode=upcoming-swift
 // RUN: %FileCheck %s < %t/functions.h
 
+import CxxStdlib
+
 // RUN: %check-interop-cxx-header-in-clang(%t/functions.h)
 
 // CHECK-LABEL: namespace Functions SWIFT_PRIVATE_ATTR SWIFT_SYMBOL_MODULE("Functions") {
@@ -44,7 +46,11 @@ public func passTwoIntReturnIntNoArgLabelParamName(_ x2: CInt, _ y2: CInt) -> CI
 // CHECK:   return _impl::$s9Functions016passTwoIntReturnD19NoArgLabelParamNameys5Int32VAD_ADtF(x2, y2);
 // CHECK: }
 
-public func passVoidReturnNever() -> Never { fatalError("passVoidReturnNever") }
+public func passVoidReturnNever() -> Never {
+  print("passVoidReturnNever")
+  fflush(nil) // before exit() call
+  exit(0)
+}
 
 // CHECK-LABEL: SWIFT_INLINE_THUNK void passVoidReturnNever() noexcept SWIFT_SYMBOL("s:9Functions19passVoidReturnNevers0E0OyF") SWIFT_NORETURN {
 // CHECK-NOT: return