Reproduction of pulumi-aws issue 3986

• ISSUE-3986

• The dev stack is used to stage resources for repro
• The repro stack is used for importing staged resources back into a new stack and reproducing the issue

Usage

pulumi stack select dev
pulumi up

bash repro.sh

...
error: aws:ec2/routeTable:RouteTable resource 'pulumi-import-issue-3986-rtb' has a problem: "" is not a valid CIDR block: invalid CIDR address: . Examine values at 'pulumi-import-issue-3986-rtb.routes'.