Fix evaluating empty loop condition to true.
Fix evaluating empty loop condition to true.

Bug 27351438

Change-Id: If15f0f91931f34af6e78ad773036b91ff5d57d01
Reviewed-on: https://swiftshader-review.googlesource.com/4902
Tested-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>
Reviewed-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>

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