Blur is silently ignored on export if dimensions too large

Migrated from: https://bugs.launchpad.net/inkscape/+bug/214132

Steps to reproduce:

• open Inkscape
• open sample file: Big_Blur.svg
• Select the yellow rectangle and export with 300 dpi

What happened?

• The exported PNG is fully black. (More precisely: the filter effects region of the blurred object is black)

What should have happened?

• The blur is exported. If Inkscape is unable to allocate enough memory to compute the blur, an error message should be displayed.

Inkscape Version and Operating System:

• Inkscape Version: 1.1-dev (6b4d57f5, 2020-04-01)
• Operating System: Windows 10
• Operating System version: 10.0.18362

Migration info:

Replicated since 2008 (no version given).

confirmed in svn, blur that large requires a pixel buffer of almost 3 gb, allocating it fails

I can export so the black square is visible. I have 32GB of memory, so that might explain it. It took several minutes.