Object.defineProperty([],"length",{writable:false}).push(0)
=> should throw an exception (strict = true!)

Object.defineProperty([],"length",{writable:false}).pop()
=> should throw an exception (strict = true!)

Object.defineProperty([,,],"0",{writable:false}).reverse()
=> should throw an exception (strict = true!)

Object.defineProperty([],"length",{writable:false}).shift()
=> should throw an exception (strict = true!)

Array.prototype.sort() also calls ScriptObject#isStrictContext(), but
implementations are allowed to use a custom behaviour if array index
properties are non-writable/non-configurable. Nevertheless, I'd still
remove isStrictContext() from this method...

Object.defineProperty([],"length",{writable:false}).splice(0)
=> should throw an exception (strict = true!)

Object.defineProperty([],"length",{writable:false}).unshift()
=> should throw an exception (strict = true!)