[clang] [NFC][OpenMP] Split nesting_of_regions test (PR #87842)

[Mike Rice via cfe-commits]

mikerice1969 wrote:

This is one way to improve the overall test time. Open for other suggestions.

```
Before change:

Slowest Tests:
--------------------------------------------------------------------------
144.09s: Clang :: OpenMP/nesting_of_regions.cpp
60.81s: Clang :: OpenMP/target_defaultmap_codegen_01.cpp
56.93s: Clang :: OpenMP/target_teams_distribute_parallel_for_simd_codegen_registration.cpp
51.11s: Clang :: OpenMP/target_update_codegen.cpp
50.76s: Clang :: OpenMP/target_parallel_for_simd_codegen_registration.cpp
49.79s: Clang :: OpenMP/target_parallel_for_codegen_registration.cpp
47.64s: Clang :: OpenMP/target_teams_distribute_codegen_registration.cpp
46.50s: Clang :: OpenMP/task_depend_messages.cpp
46.20s: Clang :: OpenMP/target_teams_distribute_simd_codegen_registration.cpp
43.90s: Clang :: OpenMP/target_parallel_codegen_registration.cpp
43.56s: Clang :: OpenMP/target_simd_codegen_registration.cpp
41.28s: Clang :: OpenMP/target_teams_codegen_registration.cpp
34.68s: Clang :: OpenMP/distribute_parallel_for_simd_reduction_messages.cpp
34.51s: Clang :: OpenMP/distribute_parallel_for_reduction_messages.cpp
31.47s: Clang :: OpenMP/target_parallel_for_simd_codegen.cpp
31.03s: Clang :: OpenMP/target_parallel_generic_loop_codegen-1.cpp
30.75s: Clang :: OpenMP/atomic_compare_codegen.cpp
29.19s: Clang :: OpenMP/target_parallel_for_codegen.cpp
28.99s: Clang :: OpenMP/distribute_simd_reduction_messages.cpp
28.32s: Clang :: OpenMP/target_teams_distribute_parallel_for_reduction_messages.cpp

Tests Times:
--------------------------------------------------------------------------
[   Range   ] :: [               Percentage               ] :: [  Count  ]
--------------------------------------------------------------------------
[140s,150s) :: [                                        ] :: [   1/1401]
[130s,140s) :: [                                        ] :: [   0/1401]
[120s,130s) :: [                                        ] :: [   0/1401]
[110s,120s) :: [                                        ] :: [   0/1401]
[100s,110s) :: [                                        ] :: [   0/1401]
[ 90s,100s) :: [                                        ] :: [   0/1401]
[ 80s, 90s) :: [                                        ] :: [   0/1401]
[ 70s, 80s) :: [                                        ] :: [   0/1401]
[ 60s, 70s) :: [                                        ] :: [   1/1401]
[ 50s, 60s) :: [                                        ] :: [   4/1401]
[ 40s, 50s) :: [                                        ] :: [   6/1401]
[ 30s, 40s) :: [                                        ] :: [   7/1401]
[ 20s, 30s) :: [*                                       ] :: [  46/1401]
[ 10s, 20s) :: [**                                      ] :: [  83/1401]
[  0s, 10s) :: [***********************************     ] :: [1253/1401]
--------------------------------------------------------------------------

Testing Time: 152.87s

After split:

Slowest Tests:
--------------------------------------------------------------------------
74.79s: Clang :: OpenMP/target_teams_distribute_parallel_for_simd_codegen_registration.cpp
71.50s: Clang :: OpenMP/target_update_codegen.cpp
71.37s: Clang :: OpenMP/target_defaultmap_codegen_01.cpp
65.05s: Clang :: OpenMP/target_parallel_for_simd_codegen_registration.cpp
64.44s: Clang :: OpenMP/target_teams_distribute_simd_codegen_registration.cpp
63.47s: Clang :: OpenMP/task_depend_messages.cpp
62.47s: Clang :: OpenMP/target_parallel_for_codegen_registration.cpp
62.37s: Clang :: OpenMP/target_teams_distribute_codegen_registration.cpp
54.54s: Clang :: OpenMP/target_simd_codegen_registration.cpp
51.63s: Clang :: OpenMP/target_teams_codegen_registration.cpp
51.41s: Clang :: OpenMP/target_parallel_codegen_registration.cpp
40.03s: Clang :: OpenMP/nesting_of_regions_45.cpp
39.75s: Clang :: OpenMP/nesting_of_regions_51.cpp
39.70s: Clang :: OpenMP/nesting_of_regions_50.cpp
34.36s: Clang :: OpenMP/distribute_parallel_for_simd_reduction_messages.cpp
33.65s: Clang :: OpenMP/distribute_parallel_for_reduction_messages.cpp
32.35s: Clang :: OpenMP/target_parallel_for_simd_codegen.cpp
32.31s: Clang :: OpenMP/target_parallel_generic_loop_codegen-1.cpp
32.16s: Clang :: OpenMP/teams_distribute_parallel_for_reduction_messages.cpp
32.14s: Clang :: OpenMP/teams_distribute_parallel_for_simd_reduction_messages.cpp

Tests Times:
--------------------------------------------------------------------------
[    Range    ] :: [               Percentage               ] :: [  Count  ]
--------------------------------------------------------------------------
[70.0s,75.0s) :: [                                        ] :: [   3/1405]
[65.0s,70.0s) :: [                                        ] :: [   1/1405]
[60.0s,65.0s) :: [                                        ] :: [   4/1405]
[55.0s,60.0s) :: [                                        ] :: [   0/1405]
[50.0s,55.0s) :: [                                        ] :: [   3/1405]
[45.0s,50.0s) :: [                                        ] :: [   0/1405]
[40.0s,45.0s) :: [                                        ] :: [   1/1405]
[35.0s,40.0s) :: [                                        ] :: [   2/1405]
[30.0s,35.0s) :: [                                        ] :: [  10/1405]
[25.0s,30.0s) :: [                                        ] :: [  21/1405]
[20.0s,25.0s) :: [                                        ] :: [  26/1405]
[15.0s,20.0s) :: [                                        ] :: [  23/1405]
[10.0s,15.0s) :: [*                                       ] :: [  58/1405]
[ 5.0s,10.0s) :: [*****                                   ] :: [ 182/1405]
[ 0.0s, 5.0s) :: [******************************          ] :: [1071/1405]
--------------------------------------------------------------------------

Testing Time: 74.98s
```


https://github.com/llvm/llvm-project/pull/87842