[stdlib] Rename `VectorProtocol.*` to `VectorProtocol.scaled(by:)`. (#25381)
- Rename `VectorProtocol` scalar multiplication.
- `VectorProtocol.*` -> `VectorProtocol.scaled(by:)`
- `VectorProtocol.*=` -> `VectorProtocol.scale(by:)`
- Update `VectorProtocol` derived conformances.
- Remove TensorFlow dependency from test/Sema/struct_key_path_iterable.swift.
Exposes TF-575.