Change use of Constant Propagation Pass to SCCPPass.

[perlfu]

Constant propagation pass has been removed in upstream LLVM in favour of focusing support on SCCP.
See https://reviews.llvm.org/D84447

[amdvlk-admin]

Test summary for commit d0641d6

Driver commits used in build

• CWPACK: amd-master 7387247eb9889ddcabbc1053b9c2052e253b088e
• METROHASH: amd-master 712f76fee75d69b23a1ea8f6465752c3ccaaf9a2
• PAL: dev ea5db60841dab7d067f5010f28a980ef222bdf81
• SPVGEN: dev 8dc855026f2502ab3f45dadaf0bb802a57d6ad60
• XGL: dev 8d9da0426ba869f5f3da23fd72cfaa669ce99c25
• LLVM-PROJECT: amd-gfx-gpuopen-dev 8abd9486af1727c8c38afcfef7390d70bb7d7d89

CTS tests (Failed: 2/42770)

• Built with branch Vulkan-CTS-1.2.0.2-fetch-sources-fix
Rhel 8.2, Gfx8
• No Results
Ubuntu 20.04, Gfx10
• No Results
Ubuntu 18.04, Gfx9

• Passed: 42768/42770 (100.0%)
• Failed: 2/42770 (0.0%)

  Failures:

  FAILURE: dEQP-VK.glsl.swizzles.vector_swizzles.mediump_ivec4_w_fragment
  Stack trace: Flake
  
  FAILURE: dEQP-VK.renderpass.suballocation.multisample_resolve.r8g8b8a8_sint.samples_8
  Stack trace: Flake
  

[piotrAMD]

LGTM (modulo missing test update in ExtShaderInt8_TestSharedVarLoadStore).
Might be good to add the reference to LLVM change in the commit message - I think that would be D84447 or 599955eb56eb.

[perlfu]

LGTM (modulo missing test update in ExtShaderInt8_TestSharedVarLoadStore).
Might be good to add the reference to LLVM change in the commit message - I think that would be D84447 or 599955eb56eb.

Thanks, I will add the LLVM reference to the commit message.
I need to fix up the lit test differences.

[dstutt]

LGTM

[dstutt]

LGTM