Erroneous ImageView size computation was causing out of bounds
memory accesses whenever an ImageView only represents a subsection
of an Image. The getSizeInBytes() function now only returns the
size in bytes within the Image object from the beginning to the
end of the bytes used by the ImageView.

Bug: b/150464740
Change-Id: I0985af9cdfbb85b10336a7691f76009496bb2ae5
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43329
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>