The harness file `Test262Error.js` has not contained executable code since it
was introduced in this project [1]. The definition of the `Test262Error`
function has consistently been located in the `sta.js` harness file which test
runners are expected to inject into the test environment.
Remove the file and all references to it.
[1] See commit c33bf0e0439e6f6bf084c1524d7df8d2b41c515d
This change adds 'var' declarations for global variables to allow the tests to run in strict mode (see issue #35).
Extra care was taken to ensure the changes do not alter the test behavior, for example when implicit creation of global variables are part of the test.
Note: The change does not fix all strict mode errors due to missing 'var' declarations.
