Don't use CanHoldArm in the code generator.

CanHoldArm was ARM32 specific. Instead use a virtual
Assembler::ShifterOperandCanHold that both thumb2 and arm32
implement.

Change-Id: I33794a93caf02ee5d78d32a8471d9fd6fe4f0a00
diff --git a/compiler/utils/arm/assembler_thumb2.h b/compiler/utils/arm/assembler_thumb2.h
index cfa251a..48a3a7e 100644
--- a/compiler/utils/arm/assembler_thumb2.h
+++ b/compiler/utils/arm/assembler_thumb2.h
@@ -304,6 +304,12 @@
                       int32_t offset,
                       Condition cond = AL) OVERRIDE;
 
+  bool ShifterOperandCanHold(Register rd,
+                             Register rn,
+                             Opcode opcode,
+                             uint32_t immediate,
+                             ShifterOperand* shifter_op) OVERRIDE;
+
 
   static bool IsInstructionForExceptionHandling(uintptr_t pc);