[CodeCompletion] Skip an ASTScope assertion for labeled statements

Code completion performs 'typeCheckASTNodeAtLoc()' which ignores
'StmtChecker::ActiveLabeledStmts'. Since this is not necessary for code
completions, skip an assertion to verify the correctness of ASTScope.

rdar://problem/67102611

Author: rintaro

lib/Sema/TypeCheckStmt.cpp

@@ -691,7 +691,8 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
       // is equivalent to what we have here.
       if (LS->getStartLoc().isValid() && sourceFile &&
           SC.getASTContext().LangOpts.EnableASTScopeLookup &&
-          !SC.getASTContext().Diags.hadAnyError()) {
+          !SC.getASTContext().Diags.hadAnyError() &&
+          !SC.LeaveBraceStmtBodyUnchecked) {
         // The labeled statements from ASTScope lookup have the
         // innermost labeled statement first, so reverse it to
         // match the data structure maintained here.

validation-test/IDE/crashers_2_fixed/rdar67102611.swift

@@ -0,0 +1,6 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s > /dev/null
+
+for x in "foo" {
+    if x.#^A^# {
+    }
+}