Cleanup of mjsunit.js code and make assertEquals more strict.

test/mjsunit/regress/regress-176.js

 // Copyright 2008 the V8 project authors. All rights reserved.
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 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // See http://code.google.com/p/v8/issues/detail?id=176
 
-assertEquals("f,",
-             "foo".match(/(?:(?=(f)o))?f/).toString(),
-             "zero length match in (?:) with capture in lookahead");
-assertEquals("f,",
-             "foo".match(/(?=(f)o)?f/).toString(),
-             "zero length match in (?=) with capture in lookahead");
-assertEquals("fo,f",
-             "foo".match(/(?:(?=(f)o)f)?o/),
-             "non-zero length match with capture in lookahead");
-assertEquals("fo,f",
-             "foo".match(/(?:(?=(f)o)f?)?o/),
-             "non-zero length match with greedy ? in (?:)");
-assertEquals("fo,f",
-             "foo".match(/(?:(?=(f)o)f??)?o/),
-             "non-zero length match with non-greedy ? in (?:), o forces backtrack");
-assertEquals("fo,f",
-             "foo".match(/(?:(?=(f)o)f??)?./),
-             "non-zero length match with non-greedy ? in (?:), zero length match causes backtrack");
-assertEquals("f,",
-             "foo".match(/(?:(?=(f)o)fx)?./),
-             "x causes backtrack inside (?:)");
+assertArrayEquals(["f", undefined],
+                  "foo".match(/(?:(?=(f)o))?f/),
+                  "zero length match in (?:) with capture in lookahead");
+assertArrayEquals(["f", undefined],
+                  "foo".match(/(?=(f)o)?f/),
+                  "zero length match in (?=) with capture in lookahead");
+assertArrayEquals(["fo", "f"],
+                  "foo".match(/(?:(?=(f)o)f)?o/),
+                  "non-zero length match with capture in lookahead");
+assertArrayEquals(["fo", "f"],
+                  "foo".match(/(?:(?=(f)o)f?)?o/),
+                  "non-zero length match with greedy ? in (?:)");
+assertArrayEquals(["fo", "f"],
+                  "foo".match(/(?:(?=(f)o)f??)?o/),
+                  "non-zero length match with non-greedy ? in (?:), o forces backtrack");
+assertArrayEquals(["fo", "f"],
+                  "foo".match(/(?:(?=(f)o)f??)?./),
+                  "non-zero length match with non-greedy ? in (?:), zero length match causes backtrack");
+assertArrayEquals(["f", undefined],
+                  "foo".match(/(?:(?=(f)o)fx)?./),
+                  "x causes backtrack inside (?:)");