Provide ia32 intrinsics for bigint add, sub, quotient digit estimation, and

runtime/vm/assembler_ia32.cc

Index: runtime/vm/assembler_ia32.cc
===================================================================
--- runtime/vm/assembler_ia32.cc	(revision 40816)
+++ runtime/vm/assembler_ia32.cc	(working copy)
@@ -1598,10 +1598,17 @@
 void Assembler::idivl(Register reg) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xF7);
-  EmitUint8(0xF8 | reg);
+  EmitOperand(7, Operand(reg));
 }
 
 
+void Assembler::divl(Register reg) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0xF7);
+  EmitOperand(6, Operand(reg));
+}
+
+
 void Assembler::imull(Register dst, Register src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x0F);