Further fix a throw returning to a frame marked for lazy deopt.

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/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 524 matching lines @@
     __ Push(R1);  // Preserve result, it will be GC-d here.
   } else if (kind == kLazyDeoptFromThrow) {
     __ Push(R1);  // Preserve exception, it will be GC-d here.
     __ Push(R2);  // Preserve stacktrace, it will be GC-d here.
   }
 
   __ Push(ZR);  // Space for the result.
   __ CallRuntime(kDeoptimizeMaterializeRuntimeEntry, 0);
   // Result tells stub how many bytes to remove from the expression stack
   // of the bottom-most frame. They were used as materialization arguments.
-  __ Pop(R1);
-  __ SmiUntag(R1);
+  __ Pop(R2);
+  __ SmiUntag(R2);
   if (kind == kLazyDeoptFromReturn) {
     __ Pop(R0);  // Restore result.
   } else if (kind == kLazyDeoptFromThrow) {
     __ Pop(R1);  // Restore stacktrace.
     __ Pop(R0);  // Restore exception.
   }
   __ LeaveStubFrame();
   // Remove materialization arguments.
-  __ add(SP, SP, Operand(R1));
+  __ add(SP, SP, Operand(R2));
   __ ret();
 }
 
 
 // LR: return address + call-instruction-size
 // R0: result, must be preserved
 void StubCode::GenerateDeoptimizeLazyFromReturnStub(Assembler* assembler) {
   // Correct return address to point just after the call that is being
   // deoptimized.
   __ AddImmediate(LR, LR, -CallPattern::kDeoptCallLengthInBytes);
@@ skipping 1748 matching lines @@
 }
 
 
 void StubCode::GenerateFrameAwaitingMaterializationStub(Assembler* assembler) {
   __ brk(0);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64