During run 57477 of the windows compile run the file icudtl.dat appears to have disappeared unexpectedly.

Examining the compile step it is copied from the source at step [7323/ (and into a few subdirectories in later compilation steps) but when buildbot re-ran the build step ninja found the file missing.

There don't appear to be any references to a build rule removing it.

This doesn't happen every time, but if we can search for reasons