Remove lld-shim.rs no longer needed on wasm

Bugs are fixed upstream!

Author: alexcrichton

ci/docker/wasm32-unknown-unknown/Dockerfile

@@ -25,13 +25,3 @@ ENV CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUNNER=wasm-bindgen-test-runner
 # Install `node`
 RUN curl https://nodejs.org/dist/v10.8.0/node-v10.8.0-linux-x64.tar.xz | tar xJf -
 ENV PATH=$PATH:/node-v10.8.0-linux-x64/bin
-
-# We use a shim linker that removes `--strip-debug` when passed to LLD. While
-# this typically results in invalid debug information in release mode it doesn't
-# result in an invalid names section which is what we're interested in.
-COPY lld-shim.rs /
-ENV CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_LINKER=/tmp/lld-shim
-
-# Rustc isn't available until this container starts, so defer compilation of the
-# shim.
-ENTRYPOINT /rust/bin/rustc /lld-shim.rs -o /tmp/lld-shim && exec bash "$@"