[cxx-interop] test, enable more tests on windows

These tests require the C++ standard library

Author: hyp

test/Interop/Cxx/stdlib/import-string-view-from-std.swift

@@ -3,8 +3,6 @@
 // RUN: %target-swift-frontend %t/test.swift -c -enable-experimental-cxx-interop -Xcc -std=c++17 -Xcc -fmodules-cache-path=%t/cache -I %t/Inputs
 // RUN: find %t/cache | %FileCheck %s
 
-// REQUIRES: OS=macosx || OS=linux-gnu
-
 //--- Inputs/module.modulemap
 module CxxModule {
     header "header.h"

test/Interop/Cxx/stdlib/use-std-optional.swift

@@ -1,7 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xcc -std=c++17)
 //
 // REQUIRES: executable_test
-// REQUIRES: OS=macosx || OS=linux-gnu
 
 import StdlibUnittest
 import StdOptional

test/Interop/Cxx/stdlib/use-std-pair-typechecker.swift

@@ -1,5 +1,4 @@
 // RUN: %target-typecheck-verify-swift -I %S/Inputs -enable-experimental-cxx-interop
-// REQUIRES: OS=macosx || OS=linux-gnu
 
 import StdPair
 

test/Interop/Cxx/stdlib/use-std-pair.swift

@@ -1,8 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop)
 //
 // REQUIRES: executable_test
-//
-// REQUIRES: OS=macosx || OS=linux-gnu
 
 import StdlibUnittest
 import StdPair

test/Interop/Cxx/stdlib/use-std-vector.swift

@@ -3,9 +3,6 @@
 // %target-run-simple-swift(-I %S/Inputs -Xfrontend -enable-experimental-cxx-interop -Xcc -std=gnu++20)
 //
 // REQUIRES: executable_test
-//
-// Enable this everywhere once we have a solution for modularizing libstdc++: rdar://87654514
-// REQUIRES: OS=macosx || OS=linux-gnu
 
 import StdlibUnittest
 import StdVector