[llvm] [Tablegen] Add keywork `dump`. (PR #68793)

[Francesco Petrogalli via llvm-commits]

================
@@ -498,6 +503,18 @@ bool TGParser::resolve(const std::vector<RecordsEntry> &Source,
       else
         CheckAssert(E.Assertion->Loc, Condition, Message);
 
+    } else if (E.Dump) {
+      MapResolver R;
----------------
fpetrogalli wrote:

This code is needed to be able to dump the template parameters of a multiclass instance. In fact, if I remove it, tablegen crashes on the `dump.td` test at the function `llvm::TGParser::resolve`, when resolving the template argument `string s` of the multiclass `MC`.

https://github.com/llvm/llvm-project/pull/68793