Add 3rd argument register to X86.

Implement more instructions.

Change-Id: I3af7bbaf18eedc6537f1cfc2d57c4f6106fb5164
diff --git a/src/runtime.cc b/src/runtime.cc
index 96c4451..b340317 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -968,8 +968,7 @@
     method->SetFpSpillMask(fp_spills);
   } else if (instruction_set == kX86) {
     method->SetFrameSizeInBytes(32);
-    method->SetCoreSpillMask((1 << art::x86::EBX) | (1 << art::x86::EBP) | (1 << art::x86::ESI) |
-                             (1 << art::x86::EDI));
+    method->SetCoreSpillMask((1 << art::x86::EBP) | (1 << art::x86::ESI) | (1 << art::x86::EDI));
     method->SetFpSpillMask(0);
   } else {
     UNIMPLEMENTED(FATAL);