Remove invalid line terminator tests (#2044)

https://github.com/tc39/test262/pull/2020#issuecomment-456581449

test/language/line-terminators/invalid-string-ls.js

-// Copyright 2019 Mike Pennisi.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: LINE SEPARATOR (U+2028) within strings is not allowed
-es5id: 7.3_A2.2_T1
-esid: sec-line-terminators
-description: Insert LINE SEPARATOR (\u2028) into string
-negative:
-  phase: parse
-  type: SyntaxError
----*/
-
-$DONOTEVALUATE();
-
-'
'

test/language/line-terminators/invalid-string-ps.js

-// Copyright 2019 Mike Pennisi.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-info: PARAGRAPH SEPARATOR (U+2029) within strings is not allowed
-es5id: 7.3_A2.2_T1
-esid: sec-line-terminators
-description: Insert PARAGRAPH SEPARATOR (\u2029) into string
-negative:
-  phase: parse
-  type: SyntaxError
----*/
-
-$DONOTEVALUATE();
-
-'
'