Revert r301697 "[IR] Make add/remove Attributes use AttrBuilder instead of AttributeList"

This broke the Clang build. (Clang-side patch missing?)

Original commit message:

> [IR] Make add/remove Attributes use AttrBuilder instead of
> AttributeList
>
> This change cleans up call sites and avoids creating temporary
> AttributeList objects.
>
> NFC

llvm-svn: 301712
diff --git a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index 9dc4767..c11247c 100644
--- a/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -2290,7 +2290,8 @@
     R.addAttribute(Attribute::NoAlias);
 
   if (!R.empty())
-    AH.setAttributes(AH.getAttributes().removeAttributes(Ctx, Index, R));
+    AH.setAttributes(AH.getAttributes().removeAttributes(
+        Ctx, Index, AttributeList::get(Ctx, Index, R)));
 }
 
 void