work around unfortunate windows ci limiations

scripts/esbuild.js

@@ -179,7 +179,14 @@ module.exports = ${JSON.stringify(exit0Map, null, 2)};
 // want to read the file after it has been truncated but before the new contents
 // have been written.
 exports.writeFileAtomic = (where, contents) => {
-  const file = path.join(os.tmpdir(), 'esbuild-atomic-file-' + Math.random().toString(36).slice(2))
+  // Note: Can't use "os.tmpdir()" because that doesn't work on Windows. CI runs
+  // tests on D:\ and the temporary directory is on C:\ or the other way around.
+  // And apparently it's impossible to move files between C:\ and D:\ or something.
+  // So we have to write the file in the same directory as the destination. This is
+  // unfortunate because it will unnecessarily trigger extra watch mode rebuilds.
+  // So we have to make our tests extra robust so they can still work with random
+  // extra rebuilds thrown in.
+  const file = path.join(path.dirname(where), '.esbuild-atomic-file-' + Math.random().toString(36).slice(2))
   fs.writeFileSync(file, contents)
   fs.renameSync(file, where)
 }