[clang] [clang-format] Add option to remove leading blank lines (PR #91221)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-armv7-global-isel` running on `linaro-clang-armv7-global-isel` while building `clang` at step 6 "build stage 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/39/builds/195

Here is the relevant piece of the build log for the reference:
```
Step 6 (build stage 1) failure: 'ninja' (failure)
...
[123/272] Linking CXX executable bin/clang-move
[124/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/IncludeCleaner.cpp.o
[125/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Hover.cpp.o
[126/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/HeaderSourceSwitch.cpp.o
[127/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/IncludeFixer.cpp.o
[128/272] Linking CXX executable bin/clang-include-fixer
[129/272] Linking CXX executable bin/pp-trace
[130/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Preamble.cpp.o
[131/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Quality.cpp.o
[132/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Format.cpp.o
FAILED: tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Format.cpp.o 
/usr/local/bin/c++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_FILE_OFFSET_BITS=64 -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D_LARGEFILE_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/stage1/tools/clang/tools/extra/clangd -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/llvm/clang-tools-extra/clangd -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/llvm/clang-tools-extra/clangd/../include-cleaner/include -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/stage1/tools/clang/tools/extra/clangd/../clang-tidy -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/llvm/clang/include -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/stage1/tools/clang/include -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/stage1/include -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/llvm/llvm/include -I/home/tcwg-buildbot/worker/clang-armv7-global-isel/llvm/clang-tools-extra/pseudo/lib/../include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -fno-common -Woverloaded-virtual -Wno-nested-anon-types -O3 -DNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Format.cpp.o -MF tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Format.cpp.o.d -o tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Format.cpp.o -c /home/tcwg-buildbot/worker/clang-armv7-global-isel/llvm/clang-tools-extra/clangd/Format.cpp
../llvm/clang-tools-extra/clangd/Format.cpp:284:11: error: no member named 'KeepEmptyLinesAtTheStartOfBlocks' in 'clang::format::FormatStyle'
  284 |     Style.KeepEmptyLinesAtTheStartOfBlocks = true;
      |     ~~~~~ ^
1 error generated.
[133/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/ParsedAST.cpp.o
[134/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/Selection.cpp.o
[135/272] Linking CXX executable bin/clang-include-cleaner
[136/272] Building CXX object tools/clang/lib/Tooling/Refactoring/CMakeFiles/obj.clangToolingRefactoring.dir/Rename/USRLocFinder.cpp.o
[137/272] Linking CXX executable bin/clang-scan-deps
[138/272] Linking CXX executable bin/clang-check
[139/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/AST.cpp.o
[140/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/InlayHints.cpp.o
[141/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/ClangdLSPServer.cpp.o
[142/272] Linking CXX executable bin/clang-19
[143/272] Linking CXX executable bin/clang-repl
ninja: build stopped: subcommand failed.

```

https://github.com/llvm/llvm-project/pull/91221