[turbofan] Fix regress-694088.js for big endian.

Test regress-694088.js is adapted for execution on big endian platforms.

TEST=test/mjsunit/compiler/regress-694088.js
BUG=

Review-Url: https://codereview.chromium.org/2739403002
Cr-Commit-Position: refs/heads/master@{#43746}

test/mjsunit/compiler/regress-694088.js

@@ -2,6 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+function is_little_endian() {
+  var buffer = new ArrayBuffer(4);
+  HEAP32 = new Int32Array(buffer);
+  HEAPU8 = new Uint8Array(buffer);
+  HEAP32[0] = 255;
+  if (HEAPU8[0] === 255 && HEAPU8[3] === 0)
+    return true;
+  else
+    return false;
+}
+
 (function () {
   var buffer = new ArrayBuffer(8);
   var i32 = new Int32Array(buffer);
@@ -10,7 +21,10 @@
   function foo() {
     f64[0] = 1;
     var x = f64[0];
-    return i32[0];
+    if (is_little_endian())
+      return i32[0];
+    else
+      return i32[1];
   }
   assertEquals(0, foo());
 })();
@@ -21,9 +35,12 @@
   var i32 = new Int32Array(buffer);
 
   function foo() {
-    i32[0] = 0x10001;
+    i32[0] = 0x20001;
     var x = i32[0];
-    return i16[0];
+    if (is_little_endian())
+      return i16[0];
+    else
+      return i16[1];
   }
   assertEquals(1, foo());
 })();