jsc: Stack-use-after-scope in JSC::MarkedBlock::vm

Detailed report: https://oss-fuzz.com/testcase?key=5635965041770496 Project: jsc Fuzzer: jsfuzzer Job Type: asanjsc Platform Id: linux Crash Type: Stack-use-after-scope READ 8 Crash Address: 0x7fffb7b6bed8 Crash State: JSC::MarkedBlock::vm JSC::JSObject JSC::jsCast JSC::asObject Sanitizer: addres...