No longer statically linked

[idontusenumbers]

As of release 1.58.0, sass is no longer statically linked. This precludes the ability to trivially move sass to a directory already on PATH.

[ntkme]

The change was intentional: google/dart_cli_pkg#114

Keep in mind that it was a single file executable, but never a statically linked ELF. Dart never had any official statically linked binaries. The single file executable was a dynamically linked ELF with snapshot appended at a magic offset. Because the snapshot is not attached as an ELF section, it causes a few compatibility issues in some corner cases, which is why we decided to not ship single executable format until dart-lang/sdk#50926 get fixed.