RFR: 6176679: Application freezes when copying an animated gif image to the system clipboard

[Rajat Mahajan]

**Problem:**

On pressing the Copy button we keep waiting in AWT-EventQueue thread in reconstruct() function as we detect that we have missing information for the animated image since we are copying single frame at a time.
Due to this infinite wait the application freezes.

**Proposed Fix:**

There are conditions in the reconstruct() function that avoid entering the wait() code if we have some error reading the image , etc. So, I added the condition to avoid entering the wait() code if we are copying single frame at a time. This sounded logical to me since if we have incomplete information(single frame) about the animated image we shouldn’t keep waiting, as it leads to infinite wait. 
After this change I see the GIF image being correctly copied and animated.


**Testing:**

Added a test for this (bug6176679.java) and tested locally on my Windows machine and on mach5.

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Commit messages:
 - fix executable permission of bug6176679.java
 - fix executable permission of cupanim.gif
 - fix for 6176679

Changes: https://git.openjdk.org/jdk/pull/13414/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13414&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-6176679
  Stats: 185 lines in 3 files changed: 184 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/13414.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13414/head:pull/13414

PR: https://git.openjdk.org/jdk/pull/13414