[KnownBitsTest] Add optimality tests to some optimal impls; NFC

Adding optimality test to `add`, `sub`, `avgCeilU` and `avgFloorU`

Author: goldsteinn

llvm/unittests/Support/KnownBitsTest.cpp

@@ -305,15 +305,13 @@ TEST(KnownBitsTest, BinaryExhaustive) {
       [](const KnownBits &Known1, const KnownBits &Known2) {
         return KnownBits::add(Known1, Known2);
       },
-      [](const APInt &N1, const APInt &N2) { return N1 + N2; },
-      /*CheckOptimality=*/false);
+      [](const APInt &N1, const APInt &N2) { return N1 + N2; });
   testBinaryOpExhaustive(
       "sub",
       [](const KnownBits &Known1, const KnownBits &Known2) {
         return KnownBits::sub(Known1, Known2);
       },
-      [](const APInt &N1, const APInt &N2) { return N1 - N2; },
-      /*CheckOptimality=*/false);
+      [](const APInt &N1, const APInt &N2) { return N1 - N2; });
   testBinaryOpExhaustive("umax", KnownBits::umax, APIntOps::umax);
   testBinaryOpExhaustive("umin", KnownBits::umin, APIntOps::umin);
   testBinaryOpExhaustive("smax", KnownBits::smax, APIntOps::smax);
@@ -524,16 +522,15 @@ TEST(KnownBitsTest, BinaryExhaustive) {
       /*CheckOptimality=*/false);
 
   testBinaryOpExhaustive("avgFloorS", KnownBits::avgFloorS, APIntOps::avgFloorS,
-                         false);
+                         /*CheckOptimality=*/false);
 
-  testBinaryOpExhaustive("avgFloorU", KnownBits::avgFloorU, APIntOps::avgFloorU,
-                         false);
+  testBinaryOpExhaustive("avgFloorU", KnownBits::avgFloorU,
+                         APIntOps::avgFloorU);
 
-  testBinaryOpExhaustive("avgCeilU", KnownBits::avgCeilU, APIntOps::avgCeilU,
-                         false);
+  testBinaryOpExhaustive("avgCeilU", KnownBits::avgCeilU, APIntOps::avgCeilU);
 
   testBinaryOpExhaustive("avgCeilS", KnownBits::avgCeilS, APIntOps::avgCeilS,
-                         false);
+                         /*CheckOptimality=*/false);
 }
 
 TEST(KnownBitsTest, UnaryExhaustive) {