* Move utility classes into separate hpp/cpp files
* Move utility functions into Util.hpp/cpp

Bug: b/176981107
Change-Id: If9046f12080f1eb09378586673d871867a836a1b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51868
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>