[turbofan] Fix overly aggressive dead code elimination.

test/mjsunit/regress/regress-crbug-631318-9.js

Index: test/mjsunit/regress/regress-crbug-631318-9.js
diff --git a/test/mjsunit/compiler/regress-5158.js b/test/mjsunit/regress/regress-crbug-631318-9.js
similarity index 57%
copy from test/mjsunit/compiler/regress-5158.js
copy to test/mjsunit/regress/regress-crbug-631318-9.js
index ead5f4ed9d36bde7ddf9036f8f18bc11bc386ed3..ad472e0722ca1a94149db28def298488e78b6fca 100644
--- a/test/mjsunit/compiler/regress-5158.js
+++ b/test/mjsunit/regress/regress-crbug-631318-9.js
@@ -4,13 +4,11 @@
 
 // Flags: --allow-natives-syntax
 
-function foo(x) {
-  x = +x;
-  return (x > 0) ? x : 0 - x;
-}
-
+function foo(x) { return x - x; }
 foo(1);
-foo(-1);
-foo(0);
-%OptimizeFunctionOnNextCall(foo);
-assertEquals(2147483648, foo(-2147483648));
+foo(2);
+
+function bar(x) { foo(x); }
+%OptimizeFunctionOnNextCall(bar);
+
+assertThrows(() => bar(Symbol.toPrimitive));