Remove redundant test

This test for string literals asserts the restriction on
LegacyOctalEscapeSequence in strict mode. It is not sufficiently
distinct from the test 'legacy-octal-escape-sequence-stricts.js' to
warrant inclusion in the test suite. Because that test includes much
more thorough documentation, it should be preferred.

test/language/literals/string/7.8.4-1gs.js

-// Copyright (c) 2012 Ecma International.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-es5id: 7.8.4-1gs
-description: >
-    Strict Mode - OctalEscapeSequence(\0110) is forbidden in strict
-    mode
-negative:
-  phase: parse
-  type: SyntaxError
-flags: [onlyStrict]
----*/
-
-throw "Test262: This statement should not be evaluated.";
-
-var _7_8_4_2 = '100abc\0110def';