[DirectX] Shader Flags Analysis for ResMayNotAlias

[bharadwajy]

Implement analysis to set the flag if command-line option -res-may-alias is NOT specified AND either

• DXIL Version > 1.7 AND function uses UAVs OR
• DXIL Version <= 1.7 AND UAVs present globally

The flag should not be set at all if DXIL Version <= 1.6

AC

• -res-may-alias command-line option added
• Shader flag set appropriately
• Add tests

[Icohedron]

I put up a PR of my implementation for this shader flag analysis: #131070