bazel syntax: eliminate unnecessary array copying

Before, EvalUtils.toCollection would return a view (if given a Sequence)
but a copy if given a Dict. This makes it inefficient and also hard to reason
about. This change replaces it with Starlark.toIterable and Starlark.toArray:
the first always returns a view, the second a copy.

Also:
- CallUtils: eliminate array copying in handling of *args and **kwargs.
- Start removing Location parameters from everything we touch.
  Location is automatically added to EvalExceptions by the interpreter.
- MethodLibrary: eliminate array copies in
  sorted, reverse, tuple, list, enumerate.
- Also in string.join, string.partition. Simplify the latter function.
- Improve text of an error message.
- Declare Starlark.len, which returns the length of a string or iterable.

This change removes support for Starlark Map other than Dict, because
there are none today.

PiperOrigin-RevId: 282682290