Convert the uses of '|&' to use '2>&1 |' instead, which works on old
versions of Bash. In addition, I can back out the change to the lit
built-in shell test runner to support this.

This should fix the majority of fallout on Darwin, but I suspect there
will be a few straggling issues.

llvm-svn: 159544
diff --git a/llvm/test/Verifier/SelfReferential.ll b/llvm/test/Verifier/SelfReferential.ll
index 449ea36..c24c0eb 100644
--- a/llvm/test/Verifier/SelfReferential.ll
+++ b/llvm/test/Verifier/SelfReferential.ll
@@ -1,4 +1,4 @@
-; RUN: not llvm-as %s -o /dev/null |& grep "Only PHI nodes may reference their own value"
+; RUN: not llvm-as %s -o /dev/null 2>&1 | grep "Only PHI nodes may reference their own value"
 
 ; Test that self referential instructions are not allowed