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.h b/tools/aapt2/io/FileSystem.h
index fb6bf6e..04c6fa1 100644
--- a/tools/aapt2/io/FileSystem.h
+++ b/tools/aapt2/io/FileSystem.h
@@ -67,6 +67,7 @@
   IFile* InsertFile(const android::StringPiece& path);
   IFile* FindFile(const android::StringPiece& path) override;
   std::unique_ptr<IFileCollectionIterator> Iterator() override;
+  char GetDirSeparator() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FileCollection);