Add tests for NaN handling with Typed Arrays (#623)

Ensure that NaN values are canonicalized consistently by all invocations
of SetValueInBuffer. Also ensure that `%TypedArray%.prototype.set` and
`%TypedArray%.prototype.slice` preserve the bit-level encoding of the
source data.

Use a set of experimentally-derived expressions known to produce NaN
values with distinct bit patterns in various platforms.