Remaining occurences of this warning have been fixed. Note the warning
is also added by -Wextra so we previously explicitly disabled it with
-Wno-deprecated-copy. While removing the latter should suffice to re-
enable it, it's useful to make it explicit since support for implicit
copy constructors when a user-defined assignment operator has been
defined may be removed in the near future.

Bug: b/191417833
Change-Id: If6721ae900afd530750a7d05ccc40365924d4c25
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/55028
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>