Merging r287551:

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r287551 | jlpeyton | 2016-11-21 10:18:57 -0600 (Mon, 21 Nov 2016) | 8 lines

Fix for D25504 - segfault because of double free()-ing in shutdown code.

Paul Osmialowski pointed out a double free bug in shutdown code.  This patch
Moves the freeing of the implicit task to above the freeing of all fast memory
to prevent the double-free issue.

Differential Revision: https://reviews.llvm.org/D26860

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llvm-svn: 287560