[flang] [llvm] [flang][OpenMP] Add parsing support for Task detach (PR #112312)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-aarch64-rel-assert` running on `linaro-flang-aarch64-rel-assert` while building `flang,llvm` at step 6 "test-build-unified-tree-check-flang".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/29/builds/6009

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

```
Step 6 (test-build-unified-tree-check-flang) failure: test (failure)
******************** TEST 'Flang :: Lower/OpenMP/Todo/task_detach.f90' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/build/bin/not bbc -emit-fir -fopenmp -fopenmp-version=50 -o - /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90 2>&1 | /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/build/bin/FileCheck /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90
+ /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/build/bin/not bbc -emit-fir -fopenmp -fopenmp-version=50 -o - /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90
+ /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/build/bin/FileCheck /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90
/home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90:9:10: error: CHECK: expected string not found in input
! CHECK: not yet implemented: OpenMP Block construct clause
         ^
<stdin>:1:1: note: scanning from here
/home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90:11:7: error: Cannot read module file for module 'omp_lib': Source file 'omp_lib.mod' was not found
^
<stdin>:4:114: note: possible intended match here
/home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90:12:17: error: Must be a constant value
                                                                                                                 ^

Input file: <stdin>
Check file: /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90

-dump-input=help explains the following input dump.

Input was:
<<<<<<
           1: /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90:11:7: error: Cannot read module file for module 'omp_lib': Source file 'omp_lib.mod' was not found 
check:9'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
           2:  use omp_lib 
check:9'0     ~~~~~~~~~~~~~
           3:  ^^^^^^^ 
check:9'0     ~~~~~~~~~
           4: /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90:12:17: error: Must be a constant value 
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:9'1                                                                                                                      ?                                    possible intended match
           5:  integer (kind=omp_event_handle_kind) :: event 
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           6:  ^^^^^^^^^^^^^^^^^^^^^ 
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~
           7: bbc: semantic errors in /home/tcwg-buildbot/worker/flang-aarch64-rel-assert/llvm-project/flang/test/Lower/OpenMP/Todo/task_detach.f90 
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>>>>

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/112312