CI: Add sanitizer script

As we did for the wasm job.

In preparation for using the `run_task` script from maintainer tools we
want to have all the things that are particular to `rust-bitcoin` out of
the current `run_task` script.

The address/memory sanitizer test is specific to `hashes`. Add a script
in `hashes/contrib` and call it from the ASAN job.

No test coverage change.

.github/workflows/rust.yml

@@ -232,8 +232,8 @@ jobs:
         run: rustup component add rust-src
       - name: "Set dependencies"
         run: cp Cargo-${{ matrix.dep }}.lock Cargo.lock
-      - name: "Run test script"
+      - name: "Run sanitizer script"
-        run: ./contrib/run_task.sh asan
+        run: cd ./hashes && ./contrib/sanitizer.sh
 
   WASM: # hashes crate only.
     name: WASM - stable toolchain

contrib/run_task.sh

@@ -90,11 +90,6 @@ main() {
 	    do_bench
 	    ;;
 
-	asan)
-            # hashes crate only - hashes/contrib/test_vars.sh is sourced in this function.
-	    do_asan
-	    ;;
-
         *)
             err "Error: unknown task $task"
             ;;
@@ -254,27 +249,6 @@ do_bench() {
     done
 }
 
-do_asan() {
-    pushd "$REPO_DIR/hashes" > /dev/null
-
-    # Set ASAN_FEATURES
-    . contrib/test_vars.sh || exit 1
-
-    cargo clean
-    CC='clang -fsanitize=address -fno-omit-frame-pointer'                                        \
-      RUSTFLAGS='-Zsanitizer=address -Clinker=clang -Cforce-frame-pointers=yes'                    \
-      ASAN_OPTIONS='detect_leaks=1 detect_invalid_pointer_pairs=1 detect_stack_use_after_return=1' \
-      cargo test --lib --no-default-features --features="$ASAN_FEATURES" -Zbuild-std --target x86_64-unknown-linux-gnu
-    # There is currently a bug in the MemorySanitizer (MSAN) - disable the job for now.
-    #
-    # cargo clean
-    # CC='clang -fsanitize=memory -fno-omit-frame-pointer'                                         \
-    #   RUSTFLAGS='-Zsanitizer=memory -Zsanitizer-memory-track-origins -Cforce-frame-pointers=yes'   \
-    #   cargo test --lib --no-default-features --features="$ASAN_FEATURES" -Zbuild-std --target x86_64-unknown-linux-gnu
-
-    popd > /dev/null
-}
-
 # Check all the commands we use are present in the current environment.
 check_required_commands() {
     need_cmd cargo

hashes/contrib/sanitizer.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+#
+# Run the Address/Memory Sanitizer tests.
+
+set -euox pipefail
+
+# Run the sanitizer with these features.
+FEATURES="std io serde"
+
+cargo clean
+CC='clang -fsanitize=address -fno-omit-frame-pointer'                                        \
+  RUSTFLAGS='-Zsanitizer=address -Clinker=clang -Cforce-frame-pointers=yes'                    \
+  ASAN_OPTIONS='detect_leaks=1 detect_invalid_pointer_pairs=1 detect_stack_use_after_return=1' \
+  cargo test --lib --no-default-features --features="$FEATURES" -Zbuild-std --target x86_64-unknown-linux-gnu
+
+# There is currently a bug in the MemorySanitizer (MSAN) - disable the job for now.
+#
+# cargo clean
+# CC='clang -fsanitize=memory -fno-omit-frame-pointer'                                         \
+    #   RUSTFLAGS='-Zsanitizer=memory -Zsanitizer-memory-track-origins -Cforce-frame-pointers=yes'   \
+    #   cargo test --lib --no-default-features --features="$FEATURES" -Zbuild-std --target x86_64-unknown-linux-gnu

hashes/contrib/test_vars.sh

@@ -6,8 +6,5 @@ FEATURES_WITH_STD="io serde small-hash schemars"
 # Test all these features without "std" enabled.
 FEATURES_WITHOUT_STD="alloc serde small-hash"
 
-# Run address sanitizer with these features.
-ASAN_FEATURES="std io serde"
-
 # Run these examples.
 EXAMPLES=""