GH-734: Improve handling of lambdas that escape enclosing frame

testing/btest/language/lambda-escaping.zeek

@@ -0,0 +1,31 @@
+# @TEST-EXEC: zeek -b %INPUT >out
+# @TEST-EXEC: btest-diff out
+
+global my_func: function();
+
+event other_event()
+	{
+	local baz = 42;
+	my_func();
+	}
+
+event zeek_init() &priority=+10
+	{
+	local outer = 101;
+
+	local lambda = function()
+		{ print outer; };
+
+	lambda();
+
+	my_func = lambda;
+	my_func();
+
+	event other_event();
+	}
+
+event zeek_init() &priority=-10
+	{
+	local qux = 13;
+	my_func();
+	}