feat: add test file for aws_iam_policy with single line

Author: rdkls

tests/aws_iam_policy_single_line.tf

@@ -0,0 +1,4 @@
+ resource "aws_iam_policy" "example" {
+   # ... other configuration ...
+   policy = "{\"Version\": \"2012-10-17\", \"Statement\": {\"Effect\": \"Allow\", \"Action\": \"*\", \"Resource\":   \"*\"}}"
+ }