Cleanup: remove redundant const qualifiers for POD types

MSVC used to warn about const mismatch for arguments passed by value.
Remove these as newer versions of MSVC no longer show this warning.

source/blender/blenlib/BLI_virtual_array.hh

@@ -79,7 +79,7 @@ template<typename T> class VArrayImpl {
    * Get the element at #index. This does not return a reference, because the value may be computed
    * on the fly.
    */
-  virtual T get(const int64_t index) const = 0;
+  virtual T get(int64_t index) const = 0;
 
   /**
    * Return true when the virtual array is a plain array internally.
@@ -202,7 +202,7 @@ template<typename T> class VMutableArrayImpl : public VArrayImpl<T> {
   /**
    * Assign the provided #value to the #index.
    */
-  virtual void set(const int64_t index, T value) = 0;
+  virtual void set(int64_t index, T value) = 0;
 
   /**
    * Copy all elements from the provided span into the virtual array.