[infra] Remove copy of jsshell to legacy location
[infra] Remove copy of jsshell to legacy location

Fixes: b/186078239
Change-Id: I963af391e67734b9dc130258a871f9b0a2966858
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/214047
Reviewed-by: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk