Is bounded waiting ensured in given version of Dekker's solution for critical section problem?
A reasonable definition of bounded waiting is:


  After a process made a request to enter its critical section and before it is granted the permission to enter, there exists a bound on the number of turns that other processes are allowed to enter.  [1]


In your case each process makes its request to enter by setting its flag (line 5 for Process 0, line 20 for Process 1.  The granting of permission is the test of the other process' flag (flag[1] false on line 6 grants permission to Process 0, flag[0] false on line 21 grants permission to Process 1).

So the only way to test the bounded waiting requirement here is to consider the case that Process 0 has just tested flag[1] on line 6, and found it true, and ask, "how many times can Process 1 leave and reenter the critical section while Process 0 is stuck in the loop?"  (Hint: consider the case where Process 0 has really bad luck, and Process 1 is able to leave and reenter the critical section during Process 0's delay on line 9).

[1] source: http://www.csl.mtu.edu/cs3331.ck/common/05-Sync-Basics.pdf