lli: Switch to using ParseIRFile, for consistency with other LLVM tools.

 - Also, switch tests to not using llvm-as. They run 20% faster now, not that it matters.

llvm-svn: 118952
diff --git a/llvm/test/ExecutionEngine/test-ret.ll b/llvm/test/ExecutionEngine/test-ret.ll
index eae91f5..beec399 100644
--- a/llvm/test/ExecutionEngine/test-ret.ll
+++ b/llvm/test/ExecutionEngine/test-ret.ll
@@ -1,5 +1,4 @@
-; RUN: llvm-as %s -o %t.bc
-; RUN: lli %t.bc > /dev/null
+; RUN: lli %s > /dev/null
 
 ; test return instructions
 define void @test1() {