Fixes ABI bug in MIPS.

samples/sample_extension/test_sample_synchronous_extension.dart

Index: samples/sample_extension/test_sample_synchronous_extension.dart
===================================================================
--- samples/sample_extension/test_sample_synchronous_extension.dart	(revision 32146)
+++ samples/sample_extension/test_sample_synchronous_extension.dart	(working copy)
@@ -12,7 +12,7 @@
   }
 }
 
-void main() {
+void checkSystemRand() {
   systemSrand(17);
   var x1 = systemRand();
   var x2 = systemRand();
@@ -29,3 +29,26 @@
   check(x2 != systemRand(), "x2 != systemRand()");
   check(x3 != systemRand(), "x3 != systemRand()");
 }
+
+void checkNoScopeSystemRand() {
+  systemSrand(17);
+  var x1 = noScopeSystemRand();
+  var x2 = noScopeSystemRand();
+  var x3 = noScopeSystemRand();
+  check(x1 != x2, "x1 != x2");
+  check(x1 != x3, "x1 != x3");
+  check(x2 != x3, "x2 != x3");
+  systemSrand(17);
+  check(x1 == noScopeSystemRand(), "x1 == noScopeSystemRand()");
+  check(x2 == noScopeSystemRand(), "x2 == noScopeSystemRand()");
+  check(x3 == noScopeSystemRand(), "x3 == noScopeSystemRand()");
+  systemSrand(18);
+  check(x1 != noScopeSystemRand(), "x1 != noScopeSystemRand()");
+  check(x2 != noScopeSystemRand(), "x2 != noScopeSystemRand()");
+  check(x3 != noScopeSystemRand(), "x3 != noScopeSystemRand()");
+}
+
+void main() {
+  checkSystemRand();
+  checkNoScopeSystemRand();
+}