BigInt TypedArray tests

- add @jakobkummerow's changes
- remove EOL whitespace
- use 'Array.isArray' instead of 'instanceof Array'
- check for BigInt type in toLocaleString tests
- specify TypedArray constructor list for non-BigInt tests
- update TypedArray harness test for BigInt
- add a missing type coercion
- disable more tests for Big(U)Int64Array
- check for BigInt before using BigInt TypedArray constructors