[Fix, Test] (DirectVulkan, ShaderTranspiler, TraceReplay): repair iterationRP's missing reduction barrier

Program 203 reuses prefixSumCache for a second subgroup reduction before every workgroup invocation has consumed the first result. Add a fingerprint-gated SPIR-V pass that inserts the missing Workgroup acquire-release barrier while preserving native subgroup operations.

Keep the repair opt-in behind MOBILEGL_ITERATIONRP_FIX_BARRIER, cover insertion, pass-through, and idempotence, and enable it together with the existing iterationRP subgroup repairs for the matching Linux and Android CI retraces.

MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp

@@ -3063,6 +3063,7 @@ void main() {
         subgroupPolicy.emulateSubgroups = ShouldEmulateSubgroups(m_nativeSubgroupSupported);
         subgroupPolicy.fixIterationRPSubgroupScratch =
             m_nativeSubgroupSupported && ShouldFixIterationRPSubgroupScratch();
+        subgroupPolicy.fixIterationRPBarrier = ShouldFixIterationRPBarrier();
         subgroupPolicy.deriveNumSubgroups =
             m_nativeSubgroupSupported && ShouldDeriveNumSubgroups();
         subgroupPolicy.requireFullSubgroups = m_computeFullSubgroupsFeatureEnabled;