[builtins] Introduce proper Float64Log2 and Float64Log10 operators.

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index 9b1e8e8780b2bb4f53877e5ac06bd9602b35fbb2..a56d325ac38b5b3de4d646241e42b7d56212a35c 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -375,6 +375,8 @@ class MachineOperatorBuilder final : public ZoneObject {
   // Floating point logarithm (double-precision).
   const Operator* Float64Log();
   const Operator* Float64Log1p();
+  const Operator* Float64Log2();
+  const Operator* Float64Log10();
 
   // Floating point bit representation.
   const Operator* Float64ExtractLowWord32();