Revert Dart_PropagateError until I can track down the problems in

runtime/vm/cpu_x64.cc

Index: runtime/vm/cpu_x64.cc
===================================================================
--- runtime/vm/cpu_x64.cc	(revision 3821)
+++ runtime/vm/cpu_x64.cc	(working copy)
@@ -64,16 +64,16 @@
 }
 
 
-void CPU::JumpToErrorHandler(
+void CPU::JumpToUnhandledExceptionHandler(
     uword program_counter,
     uword stack_pointer,
     uword frame_pointer,
-    const Error& error) {
+    const UnhandledException& unhandled_exception_object) {
   // The no_gc StackResource is unwound through the tear down of
   // stack resources below.
   NoGCScope no_gc;
-  ASSERT(!error.IsNull());
-  RawError* raw_error = error.raw();
+  ASSERT(!unhandled_exception_object.IsNull());
+  RawUnhandledException* unhandled_exception = unhandled_exception_object.raw();
 
   // Prepare for unwinding frames by destroying all the stack resources
   // in the previous frames.
@@ -83,12 +83,12 @@
     isolate->top_resource()->~StackResource();
   }
 
-  // Set up the error object as the return value in RAX and continue
-  // from the invocation stub.
+  // Set up the unhandled exception object as the return value in RAX
+  // and continue from the invocation stub.
 #if defined(TARGET_OS_WINDOWS)
   UNIMPLEMENTED();
 #else
-  asm volatile("mov %[raw_error], %%rax;"
+  asm volatile("mov %[unhandled_exception], %%rax;"
                "mov %[pc], %%rbx;"
                "mov %[fp], %%rcx;"
                "mov %[sp], %%rdi;"
@@ -96,7 +96,7 @@
                "mov %%rdi, %%rsp;"
                "jmp *%%rbx;"
                :
-               : [raw_error] "m" (raw_error),
+               : [unhandled_exception] "m" (unhandled_exception),
                  [pc] "m" (program_counter),
                  [sp] "m" (stack_pointer),
                  [fp] "m" (frame_pointer));