6962045: TEST_BUG: Tests in test/java/io/Serializable leave files open

[Alan Bateman]

Many of the serialization tests leave files open and this causes 
problems, particularly on Windows, when running these tests in jtreg 
samevm mode. One failure can cascade and cause all subsequent tests to fail.

I've taken a pass over these tests so that all 115 now pass in this 
mode. The changes are trivial and are mostly just the addition of a 
finally block to close the streams. I've kept the changes to a minimum 
and more work could be done if anyone has cycles. In particular there 
are several tests that close their files but only when the test passes. 
One idea is to take a pass over these tests once ARM blocks are in and 
stable. I've changed one test to run in othervm mode as it requires a 
security manager (and I'm assuming we're not all at jtreg 4.1 yet).  
There are two tests that assumed the test is loaded by the system class 
loader. Otherwise all the changes are trivial.

I've put the webrev here:
  http://cr.openjdk.java.net/~alanb/6962045/webrev/

-Alan.