SERVER-8995 cherry picked gperftools revision 81d99f21ede7

        issue-626: Fix SetupAggressiveDecommit initialization

    This patch fixes the SetupAggressiveDecommit initialization to run after
    pageheap_ creation.  Current code it not enforcing it, since
    InitStaticVars is being called outside the static_vars module.

    Issue details:

        https://code.google.com/p/gperftools/issues/detail?id=626

    Revision details:

        https://code.google.com/p/gperftools/source/detail?r=81d99f21ede78ab8d5fec15d0055416ac1b581f3
SERVER-8995 changed gperftools version in build configuration and source files from 2.0 to 2.2