tests: tests/posix/c_lib_ext: Integration tests fail

[DanTGL]

Describe the bug

Integration tests in tests/posix/c_lib_ext fail because qemu_cortex_m0/nrf51822 doesn't have enough RAM.
I have bisected it to 85aebac

To Reproduce
Steps to reproduce the behavior:

1. Run west twister --integration -T tests/posix/c_lib_ext
2. See error

Expected behavior

The integration tests should pass

Impact

Tests fail during CI (#87529, #80450)

Logs and console output

INFO    - The following issues were found (showing the top 10 items):
INFO    - 1) tests/posix/c_lib_ext/portability.posix.c_lib_ext on qemu_cortex_m0/nrf51822 error (Not enough RAM but is one of the integration platforms)
INFO    - 2) tests/posix/c_lib_ext/portability.posix.c_lib_ext.minimal on qemu_cortex_m0/nrf51822 error (Not enough RAM but is one of the integration platforms)
INFO    - 3) tests/posix/c_lib_ext/portability.posix.c_lib_ext.newlib on qemu_cortex_m0/nrf51822 error (Not enough RAM but is one of the integration platforms)
INFO    - 4) tests/posix/c_lib_ext/portability.posix.c_lib_ext.picolibc on qemu_cortex_m0/nrf51822 error (Not enough RAM but is one of the integration platforms)

Environment (please complete the following information):

• OS: Linux
• Toolchain: Zephyr SDK
• Commit: Latest as of writing (2338f8e)

[github-actions]

Hi @DanTGL! We appreciate you submitting your first issue for our open-source project. 🌟

Even though I'm a bot, I can assure you that the whole community is genuinely grateful for your time and effort. 🤖💙

[rruuaanng]

@cfriedt It seems that this should be solved.

[rruuaanng]

In #80450

[cfriedt]

Part of the issue was that most of the testcase.yaml was copy-pasted in #81441.

The memory requirements for this test are not as high as the legacy tests/posix/common suite.