Related to https://github.com/tc39/ecma262/pull/1177

Add tests for the behavior of INT32_MIN (-2147483648) as exponent with the exponentiation operator and with Math.pow (which shares the same core algorithm in the spec, but might be differently implemented in actual implementations). (#1445)

This reverts commit a01de4a7.

The global isNaN is not precise at all, and Number.isNaN is an ES6 feature that makes it preferrable to use assert's sameValue for NaN values, as it handles it internally using the comparison.

Due to specs approximation values, some tests are invalid as the harness
helpers rely on another approximated values as Math.LN2.

Closes gh-540

Because the specific value of each constant is specified as a
host-defined approximation, only the value type may be enforced by
Test262.

Except for a small set of expected input/output pairs, both ES5 and
ES2015 define the expected return value of these methods in terms of an
"implementation-dependent approximation." This makes it inappropriate to
enforce expectations for specific values, even if expressed imprecisely.

As written, the test for `Math.random` would pass if the runtime
erroneously produced a non-numeric value. Add the necessary assertions
to guard against this case.

Note: Already uses the updated DataView function lengths from tc39/ecma262#266 (ES2016 Draft 2015-12-20)

- Remove duplicate word
- Add missing license

This function is equivalent to `$ERROR` (which is automatically included
in test environments). Remove the harness file that defines the
function, remove references to the file from test `includes` lists, and
update scripts to instead invoke the `$ERROR` function.