[DEBUG] Revert "Enable SPV_INTEL_fp_fast_math_mode (#4058)" (#4473)

This reverts commit 353d6ff.

CI link:
https://github.com/intel/intel-xpu-backend-for-triton/actions/runs/15638597833
(passed)

---------

Signed-off-by: Anatoly Myachev <[email protected]>
Co-authored-by: Whitney Tsang <[email protected]>

Author: anmyachev

third_party/intel/triton_xpu.cc

@@ -292,8 +292,8 @@ void init_triton_intel(py::module &&m) {
       for (Instruction &inst : instructions(func)) {
         if (auto *op = dyn_cast<FPMathOperator>(&inst)) {
           FastMathFlags FMF;
-          // Default to allow contract when default fp fusion is not disabled.
-          if ((!enableFpFusion.has_value() || enableFpFusion.value()) &&
+          // Allow contract when default fp fusion is enabled.
+          if ((enableFpFusion.has_value() && enableFpFusion.value()) &&
               !fastMath.has_value()) {
             if (op->getOpcode() == Instruction::FAdd ||
                 op->getOpcode() == Instruction::FMul)