Define sort order is implementation-defined when another agent is concurrently modifying the same underlying data block

[anba]

%TypedArray%.prototype.sort should have a note that the sort order is implementation-defined when another agent is concurrently modifying the same data block. So basically something similar to this note in Array.prototype.sort:

Calling comparefn(a, b) does not modify obj or any object on obj's prototype chain.