Crash in app::tools::BaseInk::prepareForPointShape

[sentry-io]

Sentry Issue: ASEPRITE-8D

EXCEPTION_ACCESS_VIOLATION_READ / 0x0: Fatal Error: EXCEPTION_ACCESS_VIOLATION_READ / 0x0
  File "inks.h", line 36, in app::tools::BaseInk::prepareForPointShape
    m_proc->prepareForPointShape(loop, firstPoint, x, y);
  File "point_shapes.h", line 230, in app::tools::BrushPointShape::transformPoint
    ink->prepareForPointShape(loop, m_firstPoint, x, y);
  File "intertwiners.h", line 596, in app::tools::IntertwineAsPixelPerfect::doTransformPoint
    Intertwine::doTransformPoint(pt, loop);
  File "intertwine.cpp", line 85, in app::tools::Intertwine::doPointshapeStrokePt
    doTransformPoint(pt, loop);
  File "intertwiners.h", line 508, in app::tools::IntertwineAsPixelPerfect::joinStroke
    doPointshapeStrokePt(stroke[0], loop);
...
(26 additional frame(s) were not displayed)

[sentry-io]

Sentry issue: ASEPRITE-K3

[martincapello]

I was able to reproduce this by following these steps:

1. Create a new "big" sprite (for instance 10000x10000 pixels).
2. With the pencil tool draw some pixels.
3. Hold down the "shift" key and begin clicking repeatedly while moving the mouse pointer in circles inside the zone marked in the following part of the screen:
   

Note 1: It is important to move the mouse pointer to trigger the editor's automatic scroll behavior while in step 3.
Note 2: I was able to reproduce this once with a 128x128 sprite...but I couldn't do it again with this sprite size.

[martincapello]

Reopening this because the proposed fix breaks several tools.