[wasm] [asm.js] Fix asm.js issues around floating point globals.

test/mjsunit/wasm/asm-wasm.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --validate-asm --allow-natives-syntax
 
 var stdlib = this;
 
 function assertValidAsm(func) {
   assertTrue(%IsAsmWasmCode(func));
@@ skipping 1610 matching lines @@
       return 44;
     } else {
       return 55;
     }
     return 0;
   }
   return {caller: caller};
 }
 
 assertWasm(55, TestNotOne);
+
+
+function TestDotfulFloat(stdlib) {
+  "use asm";
+  var fround = stdlib.Math.fround;
+  var foo = fround(55.0);
+  function caller() {
+    return +foo;
+  }
+  return {caller: caller};
+}
+
+assertWasm(55, TestDotfulFloat);
+
+
+function TestDotlessFloat(stdlib) {
+  "use asm";
+  var fround = stdlib.Math.fround;
+  var foo = fround(55);
+  function caller() {
+    return +foo;
+  }
+  return {caller: caller};
+}
+
+assertWasm(55, TestDotlessFloat);
+
+
+function TestFloatGlobals(stdlib) {
+  "use asm";
+  var fround = stdlib.Math.fround;
+  var foo = fround(1.25);
+  function caller() {
+    foo = fround(foo + fround(1.0));
+    foo = fround(foo + fround(1.0));
+    return +foo;
+  }
+  return {caller: caller};
+}
+
+assertWasm(3.25, TestFloatGlobals);