[Clang importer] Don't insert members found via lookup into the wrong context.

Discovered while investigating rdar://85840928.

Author: DougGregor

lib/ClangImporter/ImportDecl.cpp

@@ -9780,7 +9780,8 @@ static void loadAllMembersOfRecordDecl(StructDecl *recordDecl) {
       continue;
 
     for (auto found : recordDecl->lookupDirect(name)) {
-      if (addedMembers.insert(found).second)
+      if (addedMembers.insert(found).second &&
+          found->getDeclContext() == recordDecl)
         recordDecl->addMember(found);
     }
   }

validation-test/compiler_crashers_2_fixed/0212-rdar85840928.swift

@@ -0,0 +1,9 @@
+// RUN: %target-swift-frontend -import-objc-header %S/Inputs/0212-header.h -emit-sil %s
+
+extension MyPoint {
+  var x: Int { Int(y) }
+}
+
+public func printIt(point: MyPoint) {
+  print(point)
+}

validation-test/compiler_crashers_2_fixed/Inputs/0212-header.h

@@ -0,0 +1,3 @@
+typedef struct {
+  double x, y;
+} MyPoint;