Simplify lookup table cleanup code. No functionality change.

lib/AST/NameLookup.cpp

@@ -980,9 +980,6 @@ class swift::MemberLookupTable {
   /// Create a new member lookup table.
   explicit MemberLookupTable(ASTContext &ctx);
 
-  /// Destroy the lookup table.
-  void destroy();
-
   /// Update a lookup table with members from newly-added extensions.
   void updateLookupTable(NominalTypeDecl *nominal);
 
@@ -1039,10 +1036,6 @@ class ClassDecl::ObjCMethodLookupTable
                                 StoredObjCMethods>
 {
 public:
-  void destroy() {
-    this->~ObjCMethodLookupTable();
-  }
-
   // Only allow allocation of member lookup tables using the allocator in
   // ASTContext or by doing a placement new.
   void *operator new(size_t Bytes, ASTContext &C,
@@ -1059,7 +1052,7 @@ MemberLookupTable::MemberLookupTable(ASTContext &ctx) {
   // Register a cleanup with the ASTContext to call the lookup table
   // destructor.
   ctx.addCleanup([this]() {
-    this->destroy();
+    this->~MemberLookupTable();
   });
 }
 
@@ -1127,10 +1120,6 @@ void MemberLookupTable::updateLookupTable(NominalTypeDecl *nominal) {
   }
 }
 
-void MemberLookupTable::destroy() {
-  this->~MemberLookupTable();
-}
-
 void NominalTypeDecl::addedMember(Decl *member) {
   // If we have a lookup table, add the new member to it.
   if (LookupTable.getPointer()) {
@@ -1218,7 +1207,7 @@ void ClassDecl::createObjCMethodLookup() {
   // Register a cleanup with the ASTContext to call the lookup table
   // destructor.
   ctx.addCleanup([this]() {
-    this->ObjCMethodLookup->destroy();
+    this->ObjCMethodLookup->~ObjCMethodLookupTable();
   });
 }