*********************
function f1(a2,a3) {
  const v5 = new String(a3);
  print(v5)
  return String;
}
const v8 = new Proxy(String, {"get": f1});

try {
  v8["split"](v8);
} catch (e12) {}

*********************

With the above script as input to JSC, run JSC with the following parameters:
./jsc test.js --useConcurrentJIT=0 --jitPolicyScale=0

In LLInt(executing the above script with --jitPolicyScale=1), JSC throws an exception (symbol cannot convert into string), but in JIT, JSC doesn't throw any exception.

The problem may be in Node CallStringConstructor. When the parameter is a Symbol, DFG invoke asSymbol(argument)->descriptiveString instead of throwing an exception.