panic: Checked above the range of nextcp

[langston-barrett]

Minimized from a ChakraCore test case with treereduce

To Reproduce

function f() {
     var_0 =  Array();
    for ( var_1 = 0; ; var_1 += 1024) {
        var_0[var_1] = String.fromCodePoint(var_1);
    }
}
try {
    f();
}
catch(e) {
}

thread 'main' panicked at 'Checked above the range of `nextcp`', boa_engine/src/builtins/string/mod.rs:270:47
stack backtrace:
   0: rust_begin_unwind
             at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/panicking.rs:575:5
   1: core::panicking::panic_fmt
             at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/core/src/panicking.rs:64:14
   2: core::panicking::panic_display
             at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/core/src/panicking.rs:147:5
   3: core::panicking::panic_str
             at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/core/src/panicking.rs:131:5
   4: core::option::expect_failed
             at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/core/src/option.rs:1924:5
   5: boa_engine::builtins::string::String::from_code_point
   6: boa_engine::vm::code_block::<impl boa_engine::object::jsobject::JsObject>::call_internal
   7: boa_engine::object::internal_methods::function::function_call{{reify.shim}}
   8: <boa_engine::vm::opcode::call::Call as boa_engine::vm::opcode::Operation>::execute
   9: boa_engine::vm::<impl boa_engine::context::Context>::execute_instruction
  10: boa_engine::vm::<impl boa_engine::context::Context>::run
  11: boa_engine::vm::code_block::<impl boa_engine::object::jsobject::JsObject>::call_internal
  12: boa_engine::object::internal_methods::function::function_call{{reify.shim}}
  13: <boa_engine::vm::opcode::call::Call as boa_engine::vm::opcode::Operation>::execute
  14: boa_engine::vm::<impl boa_engine::context::Context>::execute_instruction
  15: boa_engine::vm::<impl boa_engine::context::Context>::run
  16: boa_engine::context::Context::execute
  17: boa_engine::context::Context::eval_script
  18: boa::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

I did search the issue tracker this time, like so 😄