[vm] Move uri.cc from platform to bin

https://dart-review.googlesource.com/c/sdk/+/368423 moves uri.cc from vm/ to platform/.

The goal is to move it to bin/. However, to ease the roll of https://dart-review.googlesource.com/c/sdk/+/361881 into Flutter, the FFI code in vm/ still uses uri.cc until Flutter is rolled.