Revert "[Concepts] Constraint Enforcement & Diagnostics"

This reverts commit ffa214ef22892d75340dc6720271863901dc2c90, it was
causing ASAN test failures on sanitizer-x86_64-linux-bootstrap.
diff --git a/clang/lib/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
index 671e55e..c39d4d3 100644
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -401,25 +401,7 @@
   Record.AddASTTemplateArgumentListInfo(E->getTemplateArgsAsWritten());
   for (const TemplateArgument &Arg : TemplateArgs)
     Record.AddTemplateArgument(Arg);
-  const ASTConstraintSatisfaction &Satisfaction = E->getSatisfaction();
-  Record.push_back(Satisfaction.IsSatisfied);
-  if (!Satisfaction.IsSatisfied) {
-    Record.push_back(Satisfaction.NumRecords);
-    for (const auto &DetailRecord : Satisfaction) {
-      Record.AddStmt(const_cast<Expr *>(DetailRecord.first));
-      auto *E = DetailRecord.second.dyn_cast<Expr *>();
-      Record.push_back(E == nullptr);
-      if (E)
-        Record.AddStmt(E);
-      else {
-        auto *Diag = DetailRecord.second.get<std::pair<SourceLocation,
-                                                       StringRef> *>();
-        Record.AddSourceLocation(Diag->first);
-        Record.AddString(Diag->second);
-      }
-    }
-  }
-
+  Record.push_back(E->isSatisfied());
   Code = serialization::EXPR_CONCEPT_SPECIALIZATION;
 }