Invalid URI created when parsing io library

[bwilkerson]

If I parse and resolve the dart:io library, then ask the LibraryUnit for its units, ask each unit for its source (unit.getSource()) and ask each source for it's name (source.getName()), I get back an invalid URI of the form "dart://io/io.dart/chunked_stream.dart" (note the insertion of "io.dart" in the path). We had this problem once before and it was fixed, but appears to be back again. I'll be happy to help debug this in any way, but don't know where to start.

[sethladd]

Added Triaged label.

[keertip]

Marked this as blocking #1759.

[kasperl]

Removed Area-Compiler label.
Added Area-Analyzer label.

[danrubel]

Added this to the M1 milestone.
Marked this as blocking #1759.
Unmarked this as blocking #-1759.

[scheglov]

I think Source.getName() can return just anything, it has no promise of any specific structure of returned String. There is separate Source.getUri() method.

---

cc @bwilkerson.
Set owner to @scheglov.
Added AsDesigned label.