Metal loader logic doesn't account for resources that don't match the automatic linear layout

[bob80905]

Consider the following resource declarations:

StructuredBuffer<int16_t4> In: register(t0);
RWStructuredBuffer<int16_t4> Out1 : register(u1);
RWStructuredBuffer<int16_t4> Out2 : register(u2);
RWStructuredBuffer<int16_t4> Out3 : register(u3);
RWStructuredBuffer<int16_t4> Out4 : register(u4);

StructuredBuffer<uint16_t4> UIn: register(t5);
RWStructuredBuffer<uint16_t4> UOut1 : register(u6);
RWStructuredBuffer<uint16_t4> UOut2 : register(u7);
RWStructuredBuffer<uint16_t4> UOut3 : register(u8);
RWStructuredBuffer<uint16_t4> UOut4 : register(u9);

When targeting metal, we can see from the metal reflection data that these are not laid out in source or register mapping order:

  "TopLevelArgumentBuffer": [
    { "EltOffset": 0, "Name": "", "Size": 24, "Slot": 0, "Space": 0, "Type": "SRV" },
    { "EltOffset": 24, "Name": "", "Size": 24, "Slot": 5, "Space": 0, "Type": "SRV" },
    { "EltOffset": 48, "Name": "", "Size": 24, "Slot": 1, "Space": 0, "Type": "UAV" },
    { "EltOffset": 72, "Name": "", "Size": 24, "Slot": 2, "Space": 0, "Type": "UAV" },
    { "EltOffset": 96, "Name": "", "Size": 24, "Slot": 3, "Space": 0, "Type": "UAV" },
    { "EltOffset": 120, "Name": "", "Size": 24, "Slot": 4, "Space": 0, "Type": "UAV" },
    { "EltOffset": 144, "Name": "", "Size": 24, "Slot": 6, "Space": 0, "Type": "UAV" },
    { "EltOffset": 168, "Name": "", "Size": 24, "Slot": 7, "Space": 0, "Type": "UAV" },
    { "EltOffset": 192, "Name": "", "Size": 24, "Slot": 8, "Space": 0, "Type": "UAV" },
    { "EltOffset": 216, "Name": "", "Size": 24, "Slot": 9, "Space": 0, "Type": "UAV" }
  ],

We don't currently have any logic to map these or set up explicit root signatures, so any tests with a mix of resource types only work if the order coincidentally lines up.