[clang] [Clang] Give empty template parameter mapping an empty MLTAL (PR #164051)

[Corentin Jabot via cfe-commits]

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@@ -564,12 +564,17 @@ ExprResult ConstraintSatisfactionChecker::EvaluateAtomicConstraint(
 std::optional<MultiLevelTemplateArgumentList>
 ConstraintSatisfactionChecker::SubstitutionInTemplateArguments(
     const NormalizedConstraintWithParamMapping &Constraint,
-    MultiLevelTemplateArgumentList MLTAL,
-    llvm::SmallVector<TemplateArgument> &SubstitutedOuterMost) {
+    const MultiLevelTemplateArgumentList &MLTAL,
+    llvm::SmallVector<TemplateArgument> &SubstitutedOutermost) {
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cor3ntin wrote:

Can we put these refactors in an NFC commit? Thanks

https://github.com/llvm/llvm-project/pull/164051