[clang-tools-extra] [clang-reorder-fields] Support designated initializers (PR #142150)

[Vladimir Vuksanovic via cfe-commits]

================
@@ -289,35 +321,213 @@ static void reorderFieldsInConstructor(
                      Replacements);
 }
 
+/// Replacement for broken InitListExpr::isExplicit function.
+/// TODO: Remove when InitListExpr::isExplicit is fixed.
----------------
vvuksanovic wrote:

Replaced. I can't find an open issue, but there is a comment at that function: `FIXME: This is wrong; InitListExprs created by semantic analysis have valid source locations too!`

https://github.com/llvm/llvm-project/pull/142150