Fix for 3D texture sampling
Fix for 3D texture sampling

3D texture sampling did not support width*height > MAX_USHORT(65535).
Changed for 32 bit integer computation for that multiplication to
solve this issue.

Verified with 3D texture related dEQP tests.

Bug b/26105892 chromium:763382

Change-Id: Ifd07278f6263d000620a0b525c07ed4fcbdcf2e7
Reviewed-on: https://swiftshader-review.googlesource.com/12988
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Tested-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>

bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader