Add the fake stuff for the benchmarks to the Dockerfile.

I have no idea why this is needed. But, it makes `make docker`
successful again.

Dockerfile

@@ -99,6 +99,7 @@ RUN export DEBIAN_FRONTEND=noninteractive && \
 COPY arbitrator/Cargo.* arbitrator/
 COPY ./Makefile ./
 COPY arbitrator/arbutil arbitrator/arbutil
+COPY arbitrator/bench arbitrator/bench
 COPY arbitrator/brotli arbitrator/brotli
 COPY arbitrator/caller-env arbitrator/caller-env
 COPY arbitrator/prover arbitrator/prover
@@ -127,21 +128,28 @@ RUN wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - && \
 COPY --from=brotli-library-export / target/
 COPY arbitrator/Cargo.* arbitrator/
 COPY arbitrator/arbutil arbitrator/arbutil
+COPY arbitrator/bench arbitrator/bench
 COPY arbitrator/brotli arbitrator/brotli
 COPY arbitrator/caller-env arbitrator/caller-env
 COPY arbitrator/prover/Cargo.toml arbitrator/prover/
+COPY arbitrator/prover/benches arbitrator/prover/benches
+COPY arbitrator/bench/Cargo.toml arbitrator/bench/
 COPY arbitrator/jit/Cargo.toml arbitrator/jit/
 COPY arbitrator/stylus/Cargo.toml arbitrator/stylus/
 COPY arbitrator/tools/wasmer arbitrator/tools/wasmer
 COPY arbitrator/wasm-libraries/user-host-trait/Cargo.toml arbitrator/wasm-libraries/user-host-trait/Cargo.toml
 RUN bash -c 'mkdir arbitrator/{prover,jit,stylus}/src arbitrator/wasm-libraries/user-host-trait/src'
 RUN echo "fn test() {}" > arbitrator/jit/src/lib.rs && \
     echo "fn test() {}" > arbitrator/prover/src/lib.rs && \
+    echo "fn test() {}" > arbitrator/bench/src/lib.rs && \
+    echo "fn test() {}" > arbitrator/prover/benches/merkle_bench.rs && \
     echo "fn test() {}" > arbitrator/stylus/src/lib.rs && \
     echo "fn test() {}" > arbitrator/wasm-libraries/user-host-trait/src/lib.rs && \
     cargo build --manifest-path arbitrator/Cargo.toml --release --lib && \
     rm arbitrator/prover/src/lib.rs arbitrator/jit/src/lib.rs arbitrator/stylus/src/lib.rs && \
-    rm arbitrator/wasm-libraries/user-host-trait/src/lib.rs
+    rm arbitrator/wasm-libraries/user-host-trait/src/lib.rs && \
+    rm arbitrator/prover/benches/merkle_bench.rs && \
+    rm arbitrator/bench/src/lib.rs
 COPY ./Makefile ./
 COPY arbitrator/prover arbitrator/prover
 COPY arbitrator/wasm-libraries arbitrator/wasm-libraries