Move assert to CaptureListExpr::CaptureListExpr as suggested in review

Author: valeriyvan

include/swift/AST/Expr.h

@@ -4270,6 +4270,7 @@ class CaptureListExpr final : public Expr,
                   AbstractClosureExpr *closureBody)
     : Expr(ExprKind::CaptureList, /*Implicit=*/false, Type()),
       closureBody(closureBody) {
+    assert(closureBody);
     Bits.CaptureListExpr.NumCaptures = captureList.size();
     std::uninitialized_copy(captureList.begin(), captureList.end(),
                             getTrailingObjects<CaptureListEntry>());

lib/IDE/Formatting.cpp

@@ -2485,7 +2485,6 @@ class FormatWalker : public ASTWalker {
   getIndentContextFrom(CaptureListExpr *CL,
                        SourceLoc ContextLoc = SourceLoc()) {
     AbstractClosureExpr *CE = CL->getClosureBody();
-    assert(CE);
     BraceStmt *BS = CE->getBody();
     if (!BS)
       return None;