Fix Mandoline apptests on Windows.

sql/mojo/mojo_vfs.cc

Index: sql/mojo/mojo_vfs.cc
diff --git a/sql/mojo/mojo_vfs.cc b/sql/mojo/mojo_vfs.cc
index 111bd62c5c83e0033b2359dd8bf7ba7cab695ed2..8fc6da73b837a40e8d50a8324dbba70d5f86238e 100644
--- a/sql/mojo/mojo_vfs.cc
+++ b/sql/mojo/mojo_vfs.cc
@@ -61,6 +61,11 @@ filesystem::FilePtr& GetFSFile(sqlite3_file* vfs_file) {
 int MojoVFSClose(sqlite3_file* file) {
   DVLOG(1) << "MojoVFSClose(*)";
   using filesystem::FilePtr;
+  filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
+  // Must call File::Close explicitly instead of just deleting the file, since
+  // otherwise we wouldn't have an object to wait on.
+  GetFSFile(file)->Close(mojo::Capture(&error));
+  GetFSFile(file).WaitForIncomingResponse();
   GetFSFile(file).~FilePtr();
   return SQLITE_OK;
 }