Use spirv_reflect from vulkansdk

[dlarsson-adobe]

Description of Change(s)

Uses spirv_reflect from the vulkan sdk instead of a version bundled with USD
Adds the vulkan files in hgiInterop to allow building with PXR_ENABLE_VULKAN_SUPPORT=ON

Fixes Issue(s)

In environments where there are multiple clients of the Vulkan, having different versions of
spirv_reflect can cause issues at runtime. Using the version in the sdk will make it more likely
USD is in sync with the rest of the application.

• I have verified that all unit tests pass with the proposed changes
  (Note, these tests failed with or without the patch applied)

    Start 430: testUsdZipFile
1/3 Test #430: testUsdZipFile ...................***Failed    0.93 sec
    Start 683: testUsdviewNavigationKeys
2/3 Test #683: testUsdviewNavigationKeys ........***Failed   10.16 sec
    Start 699: testUsdResolverExample
3/3 Test #699: testUsdResolverExample ...........***Failed    0.71 sec

• I have submitted a signed Contributor License Agreement

[jesschimein]

Filed as internal issue #USD-8552

[davidgyu]

We think this has been addressed by ab47438

Could you verify and let us know if it looks like we need anything more to address this concern?

Thanks!