Fix failing Windows tests

Some tests were not written to run on Windows correctly. Compile also
has a bug that caused using the --zip flag to fail on Windows.
iswspace does count the non breaking space as Whiespace on Windows but
not on Unix based systems

Bug: 117156986
Change-Id: I999375162bdfdf86fb25992ee88e2962ab90b577
Test: aapt2_tests and wine aapt2_tests.exe
diff --git a/tools/aapt2/io/FileSystem.cpp b/tools/aapt2/io/FileSystem.cpp
index 16a20f4c..51cc903 100644
--- a/tools/aapt2/io/FileSystem.cpp
+++ b/tools/aapt2/io/FileSystem.cpp
@@ -128,5 +128,9 @@
   return util::make_unique<FileCollectionIterator>(this);
 }
 
+char FileCollection::GetDirSeparator() {
+  return file::sDirSep;
+}
+
 }  // namespace io
 }  // namespace aapt