[SILSymbolVisitor] Skip local conformance entries from pre-expanded macros.

(cherry picked from commit b137c6c)

Author: hborla

lib/SIL/IR/SILSymbolVisitor.cpp

@@ -238,6 +238,9 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
   void addConformances(const IterableDeclContext *IDC) {
     for (auto conformance :
          IDC->getLocalConformances(ConformanceLookupKind::NonInherited)) {
+      if (conformance->getSourceKind() == ConformanceEntryKind::PreMacroExpansion)
+        continue;
+
       auto protocol = conformance->getProtocol();
       if (Ctx.getOpts().PublicSymbolsOnly &&
           getDeclLinkage(protocol) != FormalLinkage::PublicUnique)