Support for SDIV and MLS ARM instructions, and implement DoModI using them

src/arm/assembler-arm.h

Index: src/arm/assembler-arm.h
===================================================================
--- src/arm/assembler-arm.h	(revision 12559)
+++ src/arm/assembler-arm.h	(working copy)
@@ -869,6 +869,12 @@
   void mla(Register dst, Register src1, Register src2, Register srcA,
            SBit s = LeaveCC, Condition cond = al);
 
+  void mls(Register dst, Register src1, Register src2, Register srcA,
+           Condition cond = al);
+
+  void sdiv(Register dst, Register src1, Register src2,
+            Condition cond = al);
+
   void mul(Register dst, Register src1, Register src2,
            SBit s = LeaveCC, Condition cond = al);