core: add support for disabling THPs (#39085)

core: add support for disabling THPs (#39085)

Transparent Hugepages (THP) is a Linux kernel feature that manages
memory using larger pages (2MB on x86, compared to the default 4KB). The
main goal is to improve memory management efficiency and system
performance, especially for memory-intensive applications. However, it
can cause drawbacks in some scenarios, such as memory regression and
latency spikes. THP policy is governed for the entire system via
/sys/kernel/mm/transparent_hugepage/enabled.
However, it can be overridden for individual workloads via prctl(2) call.
MemoryTHP= is used to disable THPs at exec-invoke to stop providing THPs
for workloads where the drawbacks outweigh the advantages. When set to
"disable", MemoryTHP= disables THPs completely for the process,
irrespective of global THP controls.

[1] https://man7.org/linux/man-pages/man2/PR_SET_THP_DISABLE.2const.html
[2] https://man7.org/linux/man-pages/man2/madvise.2.html
[3] https://github.com/torvalds/linux/commit/9dc21bbd62edeae6f63e6f25e1edb7167452457b