Fix trigonometric intrinsics: if allocation fails remember to release the loaded value on FPU stack.

runtime/vm/intrinsifier_ia32.cc

Index: runtime/vm/intrinsifier_ia32.cc
===================================================================
--- runtime/vm/intrinsifier_ia32.cc	(revision 5985)
+++ runtime/vm/intrinsifier_ia32.cc	(working copy)
@@ -1053,10 +1053,11 @@
   const Class& double_class = Class::ZoneHandle(
       Isolate::Current()->object_store()->double_class());
   __ LoadObject(EBX, double_class);
+  Label alloc_failed;
   AssemblerMacros::TryAllocate(assembler,
                                double_class,
                                EBX,  // Class register.
-                               &fall_through,
+                               &alloc_failed,
                                EAX);  // Result register.
   __ fstpl(FieldAddress(EAX, Double::value_offset()));
   __ ret();
@@ -1068,6 +1069,10 @@
   __ popl(EAX);
   __ jmp(&double_op);
 
+  __ Bind(&alloc_failed);
+  __ ffree(0);
+  __ fincstp();
+
   __ Bind(&fall_through);
 }