BigInt: fix, set only BigInts to index to avoid false negatives

...ternals/DefineOwnProperty/BigInt/detached-buffer-realm.js

...ors/internals/DefineOwnProperty/BigInt/detached-buffer.js

...efineOwnProperty/BigInt/key-is-greater-than-last-index.js

...ernals/DefineOwnProperty/BigInt/key-is-lower-than-zero.js

...s/internals/DefineOwnProperty/BigInt/key-is-minus-zero.js

.../internals/DefineOwnProperty/BigInt/key-is-not-integer.js

...nProperty/BigInt/key-is-numericindex-desc-configurable.js

...roperty/BigInt/key-is-numericindex-desc-not-enumerable.js

...nProperty/BigInt/key-is-numericindex-desc-not-writable.js

...onstructors/internals/Set/BigInt/detached-buffer-realm.js