Make arm assembler explicitly take both registers for load/store-pair.

runtime/vm/assembler_arm_test.cc

 // Copyright (c) 2013, 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_ARM)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/os.h"
@@ skipping 1132 matching lines @@
 ASSEMBLER_TEST_RUN(Ldrh1, test) {
   EXPECT(test != NULL);
   typedef int (*Tst)() DART_UNUSED;
   EXPECT_EQ(0xff, EXECUTE_TEST_CODE_INT32(Tst, test->entry()));
 }
 
 
 ASSEMBLER_TEST_GENERATE(Ldrd, assembler) {
   __ mov(IP, Operand(SP));
   __ sub(SP, SP, Operand(kWordSize*30));
-  __ strd(R2, SP, 0);
-  __ strd(R0, IP, (-kWordSize*28));
-  __ ldrd(R2, IP, (-kWordSize*28));
-  __ ldrd(R0, SP, 0);
+  __ strd(R2, R3, SP, 0);
+  __ strd(R0, R1, IP, (-kWordSize*28));
+  __ ldrd(R2, R3, IP, (-kWordSize*28));
+  __ ldrd(R0, R1, SP, 0);
   __ add(SP, SP, Operand(kWordSize*30));
   __ sub(R0, R0, Operand(R2));
   __ add(R1, R1, Operand(R3));
   __ bx(LR);
 }
 
 
 ASSEMBLER_TEST_RUN(Ldrd, test) {
   EXPECT(test != NULL);
   typedef int64_t (*Tst)(int64_t r0r1, int64_t r2r3) DART_UNUSED;
@@ skipping 2822 matching lines @@
   EXPECT_EQ(ICData::kInt64RangeBit, RANGE_OF(Integer::New(kMinInt64)));
 
   EXPECT_EQ(-1, RANGE_OF(Bool::True().raw()));
 
 #undef RANGE_OF
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM