Cleanup: quiet warning

Not cherry picked, just included for release build.

Follow up to previous commit, proper fix for T46284, incorrect Texture
shading in Texture paint mode and cycles

Revert "Fix T46284: Texture paint, wrong shading mode"

Should fix T46616 but will reintroduce T46284.
The second, original bug needs different handling

This reverts commit 904db487a7b14c31282fe0284612159a836657cd.

Fix T44231: Freestyle causes crash on render.

The reported crash was confirmed as a segmentation fault in std::sort().
The cause of the crash was traced down to a binary comparison function
that was not satisfying the so-called strict weak ordering requirements of
the C++ standard sorting function. Specifically, the comparison operator
has to return false when two objects are equivalent (i.e., comp(a, a) must
be false), but that requirement was not met.

Since the binary comparison operator in question could be a user-defined
Python function, here a safety measure is implemented in the C++ layer to
make sure the aforementioned requirement is always satisfied.

Temporary "fix" for crash when saving OpenEXR Multi-View from Image Editor

Fix T46617 File Output Node seems to save only black images into OpenEXR image data

If the node output had only one layer, it would be detected as singlelayer, and it would miss the blender exr header string

Freestyle: Fix for 'Distance from Object' modifiers without a target object.

'Distance from Object' color/alpha/thickness modifiers without a target
object were raising a run-time exception although it is not considered an
error condition.

Fix broken comment about our WM progress report for python (its not a progress bar at all).

Fix: Prevent warnings from popping up when trying to edit driver expressions from buttons

Previously, a warning was added to provide feedback to users trying to change the values
of driven properties why their edits would not have any effect on the propeerty. However,
it turned out that instead of only showing up when the user tried to increment/decrement/slide
the property's value, it was also firing everytime they were trying to edit the expression.
That however is not what we want at all!

This fix assumes that BUTTON_STATE_TEXT_EDITING is used for expression editing, and
BUTTON_STATE_NUM_EDITING (or everything else) refers to the user trying to adjust the
value normally.

Freestyle: minor speed-up by omitting the calculation of the smallest edge size.

BlenderFileLoader tries to find the smallest edge size but the computed value is not used.

OpenSubdiv: Fix wrong handling of vertex parent

Vertex parent was not registered as CPU data requirement.

Should be in the 'a' release.

Fix T46606: Trackball Rotate jumps releasing shift

Fix T46605: Compositing causes access violation when rendering from command line

Seems was caused by the race condition in the stats printing, should be all fine now.

Nice for 'a' release.

Fix T46604: Crash in ChainPredicateIterator instantiated without predicates.

Also fixed a potential crash in the copy constructor case.

Fix T46599: Copy Rotation behaves erratically when Use Y is disabled

When the "Use Y" option in the Copy Rotation constraint is disabled, the constraint
behaves eratically when rotating all the target on all axes at the same time.
This is partially to be expected due to the way that euler rotations work
(i.e. the rotation orders stuff - you should use a rotation order based on most to
least important/significant rotations). Hence, by locking Y, you're causing accuracy
problems for Z.

What was not expected though was that changing the rotation orders on the objects
involved (for the record, it's the constraint owner that counts) did nothing.
It turns out that for objects, the rotation order settings were getting ignored!
This commit fixes this problem, and this particular case can be resolved by using
"XZY".

Notes:
* Since all object constraints were previously working on the assumption that they
used XYZ (default) order, it is possible that this change may have the unintended
consequence of changing the behaviour of some rigs which relied on the buggy
behaviour. Hopefully this will be a rare occurrence.

Fix: Missing update after scrubbing time in Graph Editor

Sometimes the timeline header didn't update after time-scrubbing in the graph
editor ends, leaving the "Pause" button visible until the next refresh of the
timeline (e.g. on mouse over)

Correct own error w/ snap-scale T46503

Don't use nan for comparisons.

Fix invalid exceptions w/ preview API

D1575 by @januz

Fix error in bone UI

Fix T46538: Mark and Clear Seam in UV Editor, assigning Hotkeys.

UV Editor keymap is not bound to a given editor (spacetype)...