Hoist resource variables using a global initializer function correctly

[ArielG-NV]

Fixes: #4874 Goal: Hoist resource variables using a global initializer function in such a way that any global with initializer function has any possible resource variables hoisted into their use location directly (otherwise many targets won't work). Changes:

1. If legalize a global kIROp and it creates a global, make a GlobalVar

[only done for resource variables for simplicity of legalization pass]

2. Add a legalization pass that moves any global GlobalVar stores (initializers) into the GlobalVar init block
3. If we have a GlobalVar which is computed to be an alias (direct assignment to another variable), hoist the alias's value into IRGlobalVar use-sites.