Update length descriptor tests for Math properties

test/built-ins/Math/acosh/acosh-length.js

test/built-ins/Math/acosh/length.js

test/built-ins/Math/asinh/asinh-length.js

test/built-ins/Math/asinh/length.js

test/built-ins/Math/atanh/atanh-length.js

test/built-ins/Math/atanh/length.js

test/built-ins/Math/cbrt/cbrt-length.js

test/built-ins/Math/cbrt/length.js

test/built-ins/Math/cosh/cosh-length.js

test/built-ins/Math/cosh/length.js

test/built-ins/Math/expm1/expm1-length.js

test/built-ins/Math/expm1/length.js

test/built-ins/Math/hypot/Math.hypot_lengthProp.js

test/built-ins/Math/hypot/length.js

test/built-ins/Math/imul/imul-length.js

test/built-ins/Math/imul/length.js

test/built-ins/Math/log10/Log10-length.js

test/built-ins/Math/log10/length.js

test/built-ins/Math/log1p/Log1p-length.js

test/built-ins/Math/log1p/length.js