GAPI test fails on RISC-V

[asenyaev]

OpenCV version: 4.5.2-pre, Last reproduced: ad333e0

The test fails from time to time on cross build for RISC-V + QEMU: https://build.opencv.org.cn/job/nightly-master/job/ubuntu-20.04-riscv64/119/

Error message:

unknown file
C++ exception with description "OpenCV(4.5.2-pre) /home/opencv-cn/slave/workspace/nightly-master/ubuntu-20.04-riscv64/opencv/modules/gapi/include/opencv2/gapi/streaming/cap.hpp:70: error: (-215:Assertion failed) false && "Couldn't grab the very first frame" in function 'prep'
" thrown in the test body.

System information (version)

• OpenCV => ❔
• Operating System / Platform => ❔
• Compiler => ❔

Detailed description

Steps to reproduce

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues,
  forum.opencv.org, Stack Overflow, etc and have not found solution
• I updated to latest OpenCV version and the issue is still there
• There is reproducer code and related data files: videos, images, onnx, etc

[alalek]

Similar cases cases covered by #18819 some time ago.
Issue is reproducible on CentOS builder (no enabled video codecs).

/cc @mpashchenkov

[dmatveev]

@mpashchenkov is this what we fix or plan to fix? I believe #19861 is the solution isn't it?