CI: Enable Physim threshold check for tests on Caracal and GH
This MR adds support for configurable timing threshold files in PhySim
tests.
- Introduces a new CMake cache variable PHYSIM_CHECK_FILES to specify
one or more timing threshold files (semicolon-separated).
- Enables optional enforcement of timing thresholds check in PhySim
tests without changing existing test definitions.
- Defines timing thresholds for LDPC encoding/decoding in nr_ulsim,
nr_dlsim and ldpctest on Caracal and GH machines.