[turbofan] Don't propagate truncations if output is tagged.

test/mjsunit/compiler/regress-644048.js

Index: test/mjsunit/compiler/regress-644048.js
diff --git a/test/mjsunit/regress/regress-crbug-629062.js b/test/mjsunit/compiler/regress-644048.js
similarity index 77%
copy from test/mjsunit/regress/regress-crbug-629062.js
copy to test/mjsunit/compiler/regress-644048.js
index 228ae6d2d5012e8d00b19fe5093ed54f7de4ded9..ee2dd6edef4792a5777f77ba9fcc1eff12d87a07 100644
--- a/test/mjsunit/regress/regress-crbug-629062.js
+++ b/test/mjsunit/compiler/regress-644048.js
@@ -5,10 +5,12 @@
 // Flags: --allow-natives-syntax
 
 function foo(x) {
-  return 1 + ((1 == 0) && undefined);
+  (x
+      ? (!0 / 0)
+         : x) | 0
 }
 
-foo(false);
-foo(false);
+foo(1);
+foo(2);
 %OptimizeFunctionOnNextCall(foo);
-foo(true);
+foo(3);