b120f7b [test] Add tests for self usage in arith_uint256 (Karl-Johan Alm)
08b17de [arith_uint256] Do not destroy *this content if passed-in operator may reference it (Karl-Johan Alm)
Pull request description:
Before this fix (see test commit), `v *= v` would result in `0` because `operator*=` set `*this` (`==b`) to `0` at the start. This patch changes the code to use `a` as temporary for `*this`~~, with drawback that `*this` is set to `a` at the end, an extra `=` operation in other words~~.
Tree-SHA512: 8028a99880c3198a39c4bcc5056169735ba960625d553e15c0317510a52940c875f7a1fefe14e1af7fcf10c07a246411994a328cb1507bf3eaf1b6e7425390dc
Backport of Core PR12537