Script runs a cmake command to generate and open a png with a dependency
graph of currently enabled SwiftShader targets. Note that you should use
CMake 3.17 to get the best looking graph, as many fixes and improvements
were made to the graphviz support in 3.17.

Bug: none
Change-Id: Ie84eb18377b15f823bcdfe34612bf532502adf48
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43748Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>