[turbofan] Add missing Float32 -> TaggedSigned conversion.

test/mjsunit/regress/regress-crbug-656275.js

Index: test/mjsunit/regress/regress-crbug-656275.js
diff --git a/test/mjsunit/compiler/regress-644048.js b/test/mjsunit/regress/regress-crbug-656275.js
similarity index 76%
copy from test/mjsunit/compiler/regress-644048.js
copy to test/mjsunit/regress/regress-crbug-656275.js
index ee2dd6edef4792a5777f77ba9fcc1eff12d87a07..74b29c14586a6b20f83993ea16488722b27efd46 100644
--- a/test/mjsunit/compiler/regress-644048.js
+++ b/test/mjsunit/regress/regress-crbug-656275.js
@@ -4,13 +4,11 @@
 
 // Flags: --allow-natives-syntax
 
-function foo(x) {
-  (x
-      ? (!0 / 0)
-         : x) | 0
-}
+var a = 1;
 
+function foo(x) { a = Math.fround(x + 1); }
+
+foo(1);
 foo(1);
-foo(2);
 %OptimizeFunctionOnNextCall(foo);
-foo(3);
+foo(1.3);