[llvm] Make llvm::telemetry::Manager::preDispatch protected. (PR #127114)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-remote-linux-win` running on `as-builder-10` while building `llvm` at step 8 "build-default".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/197/builds/2043

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

```
Step 8 (build-default) failure: cmake (failure)
...
63.360 [224/9/5078]Linking CXX executable bin\dsymutil.exe
63.389 [223/9/5079]Linking CXX executable bin\bugpoint.exe
63.409 [222/9/5080]Linking CXX static library lib\clangExtractAPI.lib
63.430 [221/9/5081]Linking CXX static library lib\clangToolingRefactoring.lib
63.481 [220/9/5082]Linking CXX static library lib\clangStaticAnalyzerCore.lib
63.515 [219/9/5083]Linking CXX static library lib\clangTransformer.lib
63.711 [218/9/5084]Linking CXX static library lib\clangStaticAnalyzerCheckers.lib
64.134 [217/9/5085]Linking CXX executable bin\lli.exe
64.179 [216/9/5086]Linking CXX static library lib\clangStaticAnalyzerFrontend.lib
64.204 [215/9/5087]Building CXX object tools\lldb\source\Core\CMakeFiles\lldbCore.dir\Telemetry.cpp.obj
FAILED: tools/lldb/source/Core/CMakeFiles/lldbCore.dir/Telemetry.cpp.obj 
ccache C:\PROGRA~1\MICROS~1\2022\COMMUN~1\VC\Tools\MSVC\1441~1.341\bin\Hostx64\x64\cl.exe  /nologo /TP -DCLANG_BUILD_STATIC -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_ENABLE_EXTENDED_ALIGNED_STORAGE -D_GLIBCXX_ASSERTIONS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -IC:\buildbot\as-builder-10\lldb-x-aarch64\build\tools\lldb\source\Core -IC:\buildbot\as-builder-10\lldb-x-aarch64\llvm-project\lldb\source\Core -IC:\buildbot\as-builder-10\lldb-x-aarch64\llvm-project\lldb\include -IC:\buildbot\as-builder-10\lldb-x-aarch64\build\tools\lldb\include -IC:\buildbot\as-builder-10\lldb-x-aarch64\build\include -IC:\buildbot\as-builder-10\lldb-x-aarch64\llvm-project\llvm\include -IC:\Python312\include -IC:\buildbot\as-builder-10\lldb-x-aarch64\llvm-project\llvm\..\clang\include -IC:\buildbot\as-builder-10\lldb-x-aarch64\build\tools\lldb\..\clang\include -IC:\buildbot\as-builder-10\lldb-x-aarch64\llvm-project\lldb\source -IC:\buildbot\as-builder-10\lldb-x-aarch64\build\tools\lldb\source -D__OPTIMIZE__ /Zc:inline /Zc:preprocessor /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd5105 -wd4324 -wd4251 -wd4275 -w14062 -we4238 /Gw /O2 /Ob2  -MD   -wd4018 -wd4068 -wd4150 -wd4201 -wd4251 -wd4521 -wd4530 -wd4589  /EHs-c- /GR- -UNDEBUG -std:c++17 /showIncludes /Fotools\lldb\source\Core\CMakeFiles\lldbCore.dir\Telemetry.cpp.obj /Fdtools\lldb\source\Core\CMakeFiles\lldbCore.dir\lldbCore.pdb /FS -c C:\buildbot\as-builder-10\lldb-x-aarch64\llvm-project\lldb\source\Core\Telemetry.cpp
C:\buildbot\as-builder-10\lldb-x-aarch64\llvm-project\llvm\include\llvm\Telemetry\Telemetry.h(152) : error C4716: 'llvm::telemetry::Manager::preDispatch': must return a value
64.574 [215/8/5088]Linking CXX executable bin\llc.exe
65.207 [215/7/5089]Linking CXX executable bin\clang-diff.exe
65.508 [215/6/5090]Linking CXX executable bin\clang-import-test.exe
66.042 [215/5/5091]Linking CXX executable bin\clang-installapi.exe
69.378 [215/4/5092]Linking CXX executable bin\clang-refactor.exe
69.383 [215/3/5093]Linking CXX executable bin\clang-extdef-mapping.exe
69.757 [215/2/5094]Linking CXX executable bin\clang-scan-deps.exe
69.868 [215/1/5095]Linking CXX shared library bin\libclang.dll
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/127114