[arm64] Fix the GetStackPointer stub to return the C stack pointer.

runtime/vm/stub_code_arm64.cc

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 1915 matching lines @@
 // R0: instance (must be preserved).
 // R1: instantiator type arguments (can be raw_null).
 // R2: function type arguments (can be raw_null).
 // R3: SubtypeTestCache.
 // Result in R1: null -> not found, otherwise result (true or false).
 void StubCode::GenerateSubtype4TestCacheStub(Assembler* assembler) {
   GenerateSubtypeNTestCacheStub(assembler, 4);
 }
 
 
-void StubCode::GenerateGetStackPointerStub(Assembler* assembler) {
-  __ mov(R0, SP);
+void StubCode::GenerateGetCStackPointerStub(Assembler* assembler) {
+  __ mov(R0, CSP);
   __ ret();
 }
 
 
 // Jump to a frame on the call stack.
 // LR: return address.
 // R0: program_counter.
 // R1: stack_pointer.
 // R2: frame_pointer.
 // R3: thread.
@@ skipping 428 matching lines @@
 }
 
 
 void StubCode::GenerateAsynchronousGapMarkerStub(Assembler* assembler) {
   __ brk(0);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64