SERVER-14048 Remove unnecessary member variables from Dump

(cherry picked from commit 435ff367fac3e02427aba5129e1f103ec603eb1e)
SERVER-14048 mongodump can't use exhaust mode with mongos

(cherry picked from commit a6793da36b0026c9b0ef50228f40472b31b5c76d)
Revert "SERVER-14048 mongodump can't use exhaust mode with mongos"

This reverts commit 6a193b142b32d954d97f16a63308815e551ed885.
Revert "SERVER-14048 Remove unnecessary member variables from Dump"

This reverts commit eed2eeacd17559b5d708920483b6c00dcc1ec21d.
Revert "SERVER-14027 Test renaming collection containing wildcard text index"

This reverts commit 505b3feffbbb1ab1da27cae77cd76296df13b9d1.
Revert "SERVER-14027 renameCollection don't pass full spec to deleteObjects"

This reverts commit 3a3922cefcbf746f85789c86f108c84d9bf26d9e.
post 2.6.2
SERVER-14027 renameCollection don't pass full spec to deleteObjects

If a collection being renamed has an index spec object which contains
a field prefixed by a dollar sign, deleteObjects will refuse to remove
the old spec object.  Uniquely identify the index in system.indexes by
{ns: ..., name: ...}.
SERVER-14027 Test renaming collection containing wildcard text index

(cherry picked from commit 969e42a89697d0cdfbb7e615f07d94745982b607)
SERVER-14048 Remove unnecessary member variables from Dump

(cherry picked from commit 435ff367fac3e02427aba5129e1f103ec603eb1e)
SERVER-14048 mongodump can't use exhaust mode with mongos

(cherry picked from commit a6793da36b0026c9b0ef50228f40472b31b5c76d)
SERVER-13681: Remove lock that was an incorrect workaround for Azure Drive write size limitations.

- Limit flushes to 2MB chunks to prevent hitting a limitation in
Azure Network Drives (XDrive) which have a 2MB file write size limitation.

(cherry picked from commit 78c068e5d63d77648954252a785b3673d6e314b7)
SERVER-13729: Fix Data File Growth on Windows

Reuse an existing lock to use as a lock to handle the race condition
between _flushAll, and the memory mapped file being closed instead
of holding LockMongoFilesxxx for an excessively long time.

(cherry picked from commit c4fa4dc85aec3b8dfd9ada7a58521d8f1bbf4fff)
SERVER-14198: Fix memory allocation reuse

In std::set<Pointer>, Pointer to a memory address is not a unique key.
Mmap_posix already used a unique key in the case memory was reused.
Added the same change to mmap_win.

(cherry picked from commit af4f086490d6ae51aa0c252df26751385683eaaa)
Merge remote-tracking branch 'upstream/v2.6' into v2.6