Handle WindowSurface::checkForResize() errors gracefully
Handle WindowSurface::checkForResize() errors gracefully

WindowSurface::checkForResize() contained an assert which got
triggered in some tests. In order to avoid this issue, this cl
gracefully handles an invalid window handle.

Change-Id: I6bace88370980e94676d4af9de0d88e561175835
Reviewed-on: https://swiftshader-review.googlesource.com/12808
Tested-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

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