Add a few Subzero intrinsics (not the atomic ones yet).

Handle:
* mem{cpy,move,set} (without optimizations for known lengths)
* nacl.read.tp
* setjmp, longjmp
* trap

Mostly see if the dispatching/organization is okay.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3882
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/321993002
diff --git a/src/IceTargetLowering.cpp b/src/IceTargetLowering.cpp
index 72a3e8c..877f717 100644
--- a/src/IceTargetLowering.cpp
+++ b/src/IceTargetLowering.cpp
@@ -116,6 +116,9 @@
   case Inst::Icmp:
     lowerIcmp(llvm::dyn_cast<InstIcmp>(Inst));
     break;
+  case Inst::IntrinsicCall:
+    lowerIntrinsicCall(llvm::dyn_cast<InstIntrinsicCall>(Inst));
+    break;
   case Inst::Load:
     lowerLoad(llvm::dyn_cast<InstLoad>(Inst));
     break;