[Autobackout][FunctionalRegression]Revert of change: 7b8b6da: Eliminate samples with the same texture coordinates

Adding ReassociatePass before GVN pass ensures the second sample gets
    eliminated.

Author: sys-igc

IGC/Compiler/CISACodeGen/ShaderCodeGen.cpp

@@ -1411,9 +1411,6 @@ void OptimizeIR(CodeGenContext *const pContext) {
       if (IGC_IS_FLAG_ENABLED(OCLEnableReassociate) && pContext->type == ShaderType::OPENCL_SHADER) {
         mpm.add(createReassociatePass());
       }
-      if (pContext->type == ShaderType::COMPUTE_SHADER) {
-        mpm.add(llvm::createReassociatePass());
-      }
 
       mpm.add(createPromoteConstantStructsPass());