docker: Add rust-sdk memcheck target.

docker: Separate and tweak cargo cache paths.

ci: Improve memcheck job targets.

cargo: Add missing debug syms to bench profile.

docker: Optimize layer copying.

Signed-off-by: Jason Volk <jason@zemos.net>

docker/Dockerfile.rust

@@ -6,9 +6,6 @@ ARG rust_target
 ARG rustup_version="1.28.2"
 ARG rustup_profile="minimal"
 
-WORKDIR /
-COPY --link --from=input . .
-
 WORKDIR ${RUST_HOME}
 RUN <<EOF
     set -eux
@@ -32,9 +29,6 @@ ARG CARGO_TERM_VERBOSE
 ARG rustup_components
 ARG cargo_installs
 
-WORKDIR /
-COPY --link --from=input . .
-
 WORKDIR ${RUST_HOME}
 ENV CARGO_TARGET="${rust_target}"
 ENV RUSTUP_HOME="${RUSTUP_HOME}"