Remove old tests that have been migrated to the v8 repo.

LayoutTests/fast/regex/malformed-escapes-expected.txt

-This page tests handling of malformed escape sequences.
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-On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
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-Testing regexp: /\ug/gm
-PASS regexp.test('ug') is true
-PASS regexp.lastIndex is 2
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-Testing regexp: /\xg/gm
-PASS regexp.test('xg') is true
-PASS regexp.lastIndex is 2
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-Testing regexp: /\c_/gm
-PASS regexp.test('\\c_') is true
-PASS regexp.lastIndex is 3
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-Testing regexp: /[\B]/gm
-PASS regexp.test('B') is true
-PASS regexp.lastIndex is 1
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-Testing regexp: /[\b]/gm
-PASS regexp.test('\b') is true
-PASS regexp.lastIndex is 1
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-Testing regexp: /\8/gm
-PASS regexp.test('\\8') is true
-PASS regexp.lastIndex is 2
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-Testing regexp: /^[\c]$/
-PASS regexp.test('c') is true
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-Testing regexp: /^[\c_]$/
-PASS regexp.test('c') is false
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-Testing regexp: /^[\c]]$/
-PASS regexp.test('c]') is true
-PASS successfullyParsed is true
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-TEST COMPLETE
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