x/debug: use arch's functions for reading floats and complex numbers.
x/debug: use arch's functions for reading floats and complex numbers.

Change-Id: Id1adfc0c52f3d7a02cc01ecb0db6f9ad61ab4352
Reviewed-on: https://go-review.googlesource.com/12348
Reviewed-by: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

golang/debug