Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID

This is done to avoid odd test failures, like the one fixed in r171243.

llvm-svn: 171246
diff --git a/llvm/test/Transforms/LoopRotate/dbgvalue.ll b/llvm/test/Transforms/LoopRotate/dbgvalue.ll
index b32ee82..6a8d308 100644
--- a/llvm/test/Transforms/LoopRotate/dbgvalue.ll
+++ b/llvm/test/Transforms/LoopRotate/dbgvalue.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -loop-rotate  %s  | FileCheck %s
+; RUN: opt -S -loop-rotate < %s | FileCheck %s
 
 declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
 declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone