core/types: improve accuracy of header.Size() (ethereum#25859)

The header.Size() method did not take the basefee into account.

core/types/block.go

@@ -117,7 +117,11 @@ var headerSize = common.StorageSize(reflect.TypeOf(Header{}).Size())
 // Size returns the approximate memory used by all internal contents. It is used
 // to approximate and limit the memory consumption of various caches.
 func (h *Header) Size() common.StorageSize {
-	return headerSize + common.StorageSize(len(h.Extra)+(h.Difficulty.BitLen()+h.Number.BitLen())/8)
+	var baseFeeBits int
+	if h.BaseFee != nil {
+		baseFeeBits = h.BaseFee.BitLen()
+	}
+	return headerSize + common.StorageSize(len(h.Extra)+(h.Difficulty.BitLen()+h.Number.BitLen()+baseFeeBits)/8)
 }
 
 // SanityCheck checks a few basic things -- these checks are way beyond what