enable mimalloc simd (#21644)

### What does this PR do?

### How did you verify your code works?

scripts/runner.node.mjs

@@ -82,6 +82,10 @@ function getNodeParallelTestTimeout(testPath) {
   return 10_000;
 }
 
+process.on("SIGTRAP", () => {
+  console.warn("Test runner received SIGTRAP. Doing nothing.");
+});
+
 const { values: options, positionals: filters } = parseArgs({
   allowPositionals: true,
   options: {