Adding better register tracking through locals and fixing branches.

LLVM does an amazing job of optimizing this. There are many opportunities
to make it better, too, by preventing spilling where not required or only
spilling/filling things when needed.

private/runtest.sh

@@ -1,16 +1,15 @@
 python xenia-build.py xethunk
 python xenia-build.py build
 
-rm build/$1*
-
 ./build/xenia/release/xenia-run \
     private/$1 \
     --optimize_ir_modules=true \
     --optimize_ir_functions=false \
     --trace_kernel_calls=true \
-    --trace_user_calls=true \
+    --trace_user_calls=false \
     --trace_instructions=false \
-    2>build/run.llvm.txt 1>build/run.txt
+    1>build/run.txt
+    #2>build/run.llvm.txt \
 
 if [ ! -s build/run.llvm.txt ]; then
   rm build/run.llvm.txt