[Turbofan]: Eliminate the check for -0 if it's not possible/observable.

test/mjsunit/mjsunit.status

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # 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
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@@ skipping 228 matching lines @@
   'deopt-with-fp-regs': [PASS, NO_IGNITION],
   'deserialize-optimize-inner': [PASS, NO_IGNITION],
   'div-mul-minus-one': [PASS, NO_IGNITION],
   'double-intrinsics': [PASS, NO_IGNITION],
   'elements-transition-hoisting': [PASS, NO_IGNITION],
   'es6/block-let-crankshaft': [PASS, NO_IGNITION],
   'es6/block-let-crankshaft-sloppy': [PASS, NO_IGNITION],
   'getters-on-elements': [PASS, NO_IGNITION],
   'harmony/do-expressions': [PASS, NO_IGNITION],
   'math-floor-of-div-minus-zero': [PASS, NO_IGNITION],
-
-  # TODO(mvstanton): restore NO_IGNITION.
-  'regress/regress-2132': [PASS, NO_VARIANTS],
-
+  'regress/regress-2132': [PASS, NO_IGNITION],
   'regress/regress-2339': [PASS, NO_IGNITION],
   'regress/regress-3176': [PASS, NO_IGNITION],
   'regress/regress-3709': [PASS, NO_IGNITION],
   'regress/regress-385565': [PASS, NO_IGNITION],
   'regress/regress-crbug-594183': [PASS, NO_IGNITION],
   'regress/regress-embedded-cons-string': [PASS, NO_IGNITION],
   'regress/regress-map-invalidation-2': [PASS, NO_IGNITION],
   'regress/regress-param-local-type': [PASS, NO_IGNITION],
   'regress/regress-prepare-break-while-recompile': [PASS, NO_IGNITION],
   'shift-for-integer-div': [PASS, NO_IGNITION],
@@ skipping 506 matching lines @@
 ##############################################################################
 ['gcov_coverage', {
   # Tests taking too long.
   'array-functions-prototype-misc': [SKIP],
 
   # Stack overflow.
   'big-array-literal': [SKIP],
 }],  # 'gcov_coverage'
 
 ]