I've met issues when running FindContours.accuracy test (uses old C-API) on a machine with 512Mb memory (RISC-V CanMV K230). While test itself consumes ~400Mb, with the system and other tests' leftovers it often gets killed with OOM error. So I propose to mark this test with 512mb tag to allow filtering it out on similar devices.

Below is memory consumption on x86_64 machine (GCC 11.4, Release build, with OCL):

Notes:

• Port to 5.x is not needed - this test will be removed with C-API there.
• Related CI PR: RISC-V: added RVV 1.0 weekly build ci-gha-workflow#165 (see failed checks)
• free -h shows 480Mi Total memory on this machine