tdf#94924: Fix handling of empty cells in OpenCL subtraction

We get correct result by simplifying the code;)

No need to have the outer "if (gid0 < X)" test around the calculation
code generated by Reduction::GenSlidingWindowFunction(). The lhs and
rhs check the gid0 range themselves and that leads to the desired
result for subtraction.

While fixing this I noticed that the handling of empty cells in
division is also wrong. Will fix in another commit.

Change-Id: Ia45bd81e692a17b0453cc79cd4673a00e119562a

sc/source/core/opencl/formulagroupcl.cxx

@@ -1732,13 +1732,8 @@ public:
                 assert(pCur);
                 assert(pCur->GetType() != formula::svDoubleVectorRef);
 
-                if (pCur->GetType() == formula::svSingleVectorRef)
-                {
-                    const formula::SingleVectorRefToken* pSVR =
-                        static_cast<const formula::SingleVectorRefToken*>(pCur);
-                    ss << "if (gid0 < " << pSVR->GetArrayLength() << "){\n";
-                }
-                else if (pCur->GetType() == formula::svDouble)
+                if (pCur->GetType() == formula::svSingleVectorRef ||
+                    pCur->GetType() == formula::svDouble)
                 {
                     ss << "{\n";
                 }