[llvm] [lit] Split Linux specific ulimit tests (PR #158390)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-solaris11-sparcv9` running on `solaris11-sparcv9` while building `llvm` at step 5 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/13/builds/9547

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'lit :: shtest-ulimit.py' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 6
not env -u FILECHECK_OPTS "/usr/bin/python3.11" /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/llvm/utils/lit/lit.py -j1 --order=lexical -a -v Inputs/shtest-ulimit | FileCheck /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/utils/lit/tests/shtest-ulimit.py
# executed command: not env -u FILECHECK_OPTS /usr/bin/python3.11 /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/llvm/utils/lit/lit.py -j1 --order=lexical -a -v Inputs/shtest-ulimit
# .---command stderr------------
# | lit.py: /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/llvm/utils/lit/lit/run.py:142: warning: Failed to raise process limit: module 'resource' has no attribute 'RLIMIT_NPROC'
# | 
# | 1 warning(s) in tests
# `-----------------------------
# executed command: FileCheck /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/utils/lit/tests/shtest-ulimit.py
# .---command stderr------------
# | /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/utils/lit/tests/shtest-ulimit.py:16:10: error: CHECK: expected string not found in input
# | # CHECK: RLIMIT_NOFILE=50
# |          ^
# | <stdin>:26:13: note: scanning from here
# | ulimit -n 50
# |             ^
# | <stdin>:33:5: note: possible intended match here
# | # | RLIMIT_NOFILE=48
# |     ^
# | 
# | Input file: <stdin>
# | Check file: /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/utils/lit/tests/shtest-ulimit.py
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |            21: Exit Code: 1 
# |            22:  
# |            23: Command Output (stdout): 
# |            24: -- 
# |            25: # RUN: at line 1 
# |            26: ulimit -n 50 
# | check:16'0                 X error: no match found
# |            27: # executed command: ulimit -n 50 
# | check:16'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            28: # RUN: at line 2 
# | check:16'0     ~~~~~~~~~~~~~~~~~
# |            29: "/usr/bin/python3.11" /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/utils/lit/tests/Inputs/shtest-ulimit/print_limits.py 
# | check:16'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            30: # executed command: /usr/bin/python3.11 /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/utils/lit/tests/Inputs/shtest-ulimit/print_limits.py 
# | check:16'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...

```

</details>

https://github.com/llvm/llvm-project/pull/158390