GH Runner: Put solc and resolc in tmp directory instead of work dir (#1049)

While working on #1047
I noticed that the `/cmd bench` command commits `solc` and `resolc`
binaries. This is unwanted.

I propose to not put the binaries into the main repo directory, but use
the `RUNNER_TEMP` directory. Then we have a general solution and don't
need to mess with manual exclusion of whatever tooling we want in the
future in the git workflow.

Example commit created by bot which shows the issue:
1854d62

Example commit which shows that fix works (no binaries present):
a4e34df

- [x] Does not require a CHANGELOG entry

Co-authored-by: fellowship-merge-bot[bot] <151052383+fellowship-merge-bot[bot]@users.noreply.github.com>

Author: skunert

.github/install-deps.sh

@@ -17,28 +17,28 @@ sudo rm -rf "$AGENT_TOOLSDIRECTORY"
 df -h
 
 # Install solc
-mkdir -p solc
-if [[ -x solc/solc ]]; then
+mkdir -p "$RUNNER_TEMP/solc"
+if [[ -x "$RUNNER_TEMP/solc/solc" ]]; then
   echo "solc already present, skipping download"
 else
   curl -Lsf --show-error --retry 5 --retry-all-errors --connect-timeout 10 --max-time 300 \
-    --output solc/solc \
+    --output "$RUNNER_TEMP/solc/solc" \
     "https://github.com/ethereum/solidity/releases/download/v${SOLC_VERSION}/${SOLC_NAME}"
-  chmod +x solc/solc
+  chmod +x "$RUNNER_TEMP/solc/solc"
 fi
 
 # Install resolc
-mkdir -p resolc
-if [[ -x resolc/resolc ]]; then
+mkdir -p "$RUNNER_TEMP/resolc"
+if [[ -x "$RUNNER_TEMP/resolc/resolc" ]]; then
   echo "resolc already present, skipping download"
 else
   curl -Lsf --show-error --retry 5 --retry-all-errors --connect-timeout 10 --max-time 300 \
-    --output resolc/resolc \
+    --output "$RUNNER_TEMP/resolc/resolc" \
     "https://github.com/paritytech/revive/releases/download/v${RESOLC_VERSION}/resolc-x86_64-unknown-linux-musl"
-  chmod +x resolc/resolc
-  ./resolc/resolc --version
+  chmod +x "$RUNNER_TEMP/resolc/resolc"
+  "$RUNNER_TEMP/resolc/resolc" --version
 fi
 
-echo "$PWD/solc" >> "$GITHUB_PATH"
-echo "$PWD/resolc" >> "$GITHUB_PATH"
+echo "$RUNNER_TEMP/solc" >> "$GITHUB_PATH"
+echo "$RUNNER_TEMP/resolc" >> "$GITHUB_PATH"