Bug 1649928: add CI jobs for Cranelift/aarch64 Wasm backend using simulator. r=sfink

This adds a new job variant `arm64-cranelift-sim` to the SpiderMonkey
build configurations, and adds a Taskherder CI configuration to run it.
The job uses the aarch64 simulator support built-in to SpiderMonkey, so
it does not need to run on native aarch64 hardware.

A few tests needed to be added to the "slow tests" list as they time out
under the simulator otherwise.

This also fixes an issue with an error message in `build-sm.sh` in which
the overloading of the backtick's meaning (code-quotes in
Markdown-world, and command interpolation in shell scripts) led to an
amusing attempt to execute parts of the error message.

Finally, this fixes an error that seems unrelated to Cranelift or
WebAssembly in a GC jit-test, wherein its way of measuring maximum stack
recursion depth was failing.

Differential Revision: https://phabricator.services.mozilla.com/D86131

js/src/devtools/automation/arm64-jittests-timeouts.txt

@@ -1 +1,2 @@
 basic/bug1610192.js
+ion/pow-base-power-of-two.js

js/src/devtools/automation/arm64-jstests-slow.txt

@@ -47,3 +47,6 @@ test262/built-ins/RegExp/CharacterClassEscapes/character-class-non-whitespace-cl
 test262/built-ins/RegExp/CharacterClassEscapes/character-class-non-digit-class-escape-flags-u.js
 test262/built-ins/RegExp/CharacterClassEscapes/character-class-non-word-class-escape-flags-u.js
 test262/built-ins/RegExp/property-escapes/generated/
+test262/built-ins/RegExp/property-escapes/generated/General_Category_-_Letter.js
+test262/built-ins/RegExp/property-escapes/generated/General_Category_-_Other.js
+test262/built-ins/RegExp/property-escapes/generated/General_Category_-_Unassigned.js

js/src/devtools/automation/variants/arm64-cranelift-sim

@@ -0,0 +1,10 @@
+{
+    "configure-args": "--enable-simulator=arm64 --enable-rust-simd",
+    "optimize": true,
+    "debug": true,
+    "env": {
+        "JSTESTS_EXTRA_ARGS": "--exclude-file={DIR}/arm64-jstests-slow.txt",
+        "JITTEST_EXTRA_ARGS": "--ignore-timeouts={DIR}/arm64-jittests-timeouts.txt --args=--wasm-compiler=cranelift"
+    },
+    "bits": 64
+}

js/src/jit-test/tests/gc/finalizationRegistry-cleanupSome-recursive.js

@@ -25,14 +25,16 @@ let registry = new FinalizationRegistry(x => {
 });
 
 // Attempt to find the maximum supported stack depth.
+var stackSize = 0;
 function findStackSize(i) {
   try {
-    return findStackSize(i + 1);
-  } catch {
-    return i;
+    stackSize = i;
+    findStackSize(i + 1);
+  } catch (e) {
+    return;
   }
 }
-const stackSize = findStackSize(0);
+findStackSize(0);
 
 // Multiply the calculated stack size by some factor just to be on the safe side.
 const exceedStackDepthLimit = stackSize * 5;

taskcluster/ci/spidermonkey/linux.yml

@@ -150,6 +150,25 @@ sm-arm64-sim-linux64/debug:
     run:
         spidermonkey-variant: arm64-sim
 
+sm-arm64-sim-cranelift-linux64/debug:
+    description: "Spidermonkey ARM64 sim with Cranelift Wasm backend"
+    index:
+        job-name: sm-arm64-sim-cranelift-linux64-debug
+    treeherder:
+        platform: linux64/debug
+        symbol: SM(arm64cl)
+    run:
+        spidermonkey-variant: arm64-cranelift-sim
+    fetches:
+        toolchain:
+            - linux64-binutils
+            - linux64-clang
+            - linux64-gcc
+            - linux64-rust
+            - linux64-rust-size
+            - linux64-cbindgen
+    run-on-projects: ['mozilla-central']
+
 sm-asan-linux64/opt:
     description: "Spidermonkey Address Sanitizer"
     index:

taskcluster/scripts/builder/build-sm.sh

@@ -45,7 +45,7 @@ else # !upload
 
 # Provide a note for users on why we don't include artifacts for these builds
 # by default, and how they can get the artifacts if they really need them.
-cat >$UPLOAD_DIR/README-artifacts.txt <<EOF
+cat >$UPLOAD_DIR/README-artifacts.txt <<'EOF'
 Artifact upload has been disabled for this build due to infrequent usage of the
 generated artifacts.  If you find yourself in a position where you need the
 shell or similar artifacts from this build, please redo your push with the