Slang-test anyhit and closesthit fails with spirv-tools upgrade

[cheneym2]

Upgrading SPIRV-Tools causes a test regression. The change in SPIRV-Tools responsible is:

0c40b591a305942abdcc090ef3fbf39d3326572d [OPT] Add SPV_KHR_ray_tracing_position_fetch to allow lists (#5757)

tests/vkray/anyhit.slang
tests/vkray/anyhit.slang.1

Supported backends: glslang spirv-dis gcc genericcpp llvm spirv-opt
error: slang-test: tests/vkray/closesthit.slang:53:15: error: CHECK-DAG: expected string not found in input
// CHECK-DAG: OpDecorate %{{.*}} BuiltIn HitTriangleVertexPositionsKHR
^

error: slang-test: actual-output:20:40: note: scanning from here
OpEntryPoint ClosestHitKHR %main "main" %42 %40 %19 %gl_PrimitiveID %13 %gl_InstanceID %ShaderRecord %colors %47
^

error: slang-test: actual-output:37:1: note: possible intended match here
OpDecorate %13 BuiltIn InstanceCustomIndexKHR
^

FAILED test: 'tests/vkray/closesthit.slang'
error: slang-test: tests/vkray/closesthit.slang:53:15: error: CHECK-DAG: expected string not found in input
// CHECK-DAG: OpDecorate %{{.*}} BuiltIn HitTriangleVertexPositionsKHR
^

error: slang-test: actual-output:17:40: note: scanning from here
OpEntryPoint ClosestHitKHR %main "main" %42 %40 %19 %gl_PrimitiveID %13 %gl_InstanceID %ShaderRecord %colors %47
^

error: slang-test: actual-output:34:1: note: possible intended match here
OpDecorate %13 BuiltIn InstanceCustomIndexKHR
^

FAILED test: 'tests/vkray/closesthit.slang.1'

[cheneym2]

Regression is specifically due to adding the vertex fetch extension to the allow list in: source/opt/aggressive_dead_code_elim_pass.cpp

It is added to several other allow lists, but those are not causing the regression.

[cheneym2]

Uploading the before (a.txt ), and after (b.txt) dumps.

a.txt
b.txt