### Memory leaks with matrix multiplication over GF(2)

Hello everyone,

I have memory leaks when I run this program:

```
#### Memory leaks with sage 8.3 and sage 8.1 !!!
n = 8
X = zero_vector(GF(2), n)
M = zero_matrix(GF(2), n, n)
for _ in range(10000000):
Y = M * X
```

I use debian buster and ~~sage-8.1-Debian_GNU_Linux_9-x86_64.~~sage-8.3-Debian_GNU_Linux_9-x86_64.

Is there something I'm doing wrong?

Thanks !