46c9043 Remove some unused functions and methods (Pieter Wuille)
Pull request description:
In the case of CKey's destructor, it seems to have been an oversight in #8753 not to delete it. At this point, it results in the move constructors/assignment operators for CKey being deleted, which may have a performance impact (requiring a pool allocation/copy/free, rather than just handing over the pointer from one CKey to another)
Tree-SHA512: 89715bafe3e0bea2c46fc92bc6a1010360a3fee2719f97b81ca379581003409b0876b50f992208a3c13c7f5b77f1866db09954e7d102f6a452fe5d7aed2044a1
Backport of Core PR11385
https://github.com/bitcoin/bitcoin/pull/11385