Support hexadecimal floats in tensor literals

Extend the recently introduced support for hexadecimal float literals to tensor
literals, which may also contain special floating point values such as
infinities and NaNs.

Modify TensorLiteralParser to store the list of tokens representing values
until the type is parsed instead of trying to guess the tensor element type
from the token kinds (hexadecimal values can be either integers or floats, and
can be mixed with both).  Maintain the error reports as close as possible to
the existing implementation to avoid disturbing the tests.  They can be
improved in a separate clean-up if deemed necessary.

PiperOrigin-RevId: 260794716