[11u] RFR: 8234149: Several regression tests do not dispose Frame at end

[Lindenmaier, Goetz]

Hi,

I am downporting this for 11.0.9-oracle parity.
I had to resolve a row of files:

bug4796987.java: OS check in context different, easy resolve.
bug6596966.java: simple resolve.  Indented code differs again in os check.
bug6470128.java, bug6580930.java, bug6827786.java, bug4202954.java, bug4624207.java
all similar indentation issues.

bug4962534.java, bug4634626.java: main method being fixed is only in 15
   because "8213110: Remove the use of applets in automatic tests" is not in 11.
   I just copied the whole main method. This way these fixes can not
   be overseen in case 8213110 is brought to 11 at some point.

http://cr.openjdk.java.net/~goetz/wr20/8234149-dispose_frame-jdk11/01/

Please review.

https://bugs.openjdk.java.net/browse/JDK-8234149
https://hg.openjdk.java.net/jdk/jdk/rev/7637e77c4c8a<https://hg.openjdk.java.net/jdk/jdk/rev/7637e77c4c8a>

Best regards,
  Goetz.