If the value corresponding to the input string cannot be
represented by an unsigned integer of the given size,
err.Err = ErrRange and the returned value is the maximum
magnitude unsigned integer of the appropriate bitSize.
This is consistent with ParseInt's behavior and the documentation.

Expand tests to test 32 bit test value tables with bitsize 32 set.
These tests fail without the fix in this CL.

Fixes #21278

Change-Id: I8aab39279ec3e31905fcbf582a916cbf6d9b95da
Reviewed-on: https://go-review.googlesource.com/55134
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>