[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-lnt` running on `linaro-clang-armv7-lnt` while building `clang` at step 6 "build stage 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/77/builds/352

Here is the relevant piece of the build log for the reference:
```
Step 6 (build stage 1) failure: 'ninja' (failure)
...
[151/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/index/Serialization.cpp.o
[152/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/index/IndexAction.cpp.o
[153/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/index/Background.cpp.o
[154/272] Building CXX object tools/clang/tools/extra/clangd/CMakeFiles/obj.clangDaemon.dir/index/BackgroundQueue.cpp.o
[155/272] Linking CXX executable bin/diagtool
[156/272] Linking CXX shared module lib/CheckerDependencyHandlingAnalyzerPlugin.so
[157/272] Linking CXX executable bin/amdgpu-arch
[158/272] Linking CXX shared module lib/SampleAnalyzerPlugin.so
[159/272] Linking CXX executable bin/clang-diff
[160/272] 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-lnt/stage1/tools/clang/tools/extra/clangd -I/home/tcwg-buildbot/worker/clang-armv7-lnt/llvm/clang-tools-extra/clangd -I/home/tcwg-buildbot/worker/clang-armv7-lnt/llvm/clang-tools-extra/clangd/../include-cleaner/include -I/home/tcwg-buildbot/worker/clang-armv7-lnt/stage1/tools/clang/tools/extra/clangd/../clang-tidy -I/home/tcwg-buildbot/worker/clang-armv7-lnt/llvm/clang/include -I/home/tcwg-buildbot/worker/clang-armv7-lnt/stage1/tools/clang/include -I/home/tcwg-buildbot/worker/clang-armv7-lnt/stage1/include -I/home/tcwg-buildbot/worker/clang-armv7-lnt/llvm/llvm/include -I/home/tcwg-buildbot/worker/clang-armv7-lnt/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-lnt/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.
[161/272] Linking CXX executable bin/arcmt-test
[162/272] Linking CXX shared module lib/CheckerOptionHandlingAnalyzerPlugin.so
[163/272] Linking CXX executable bin/llvm-strings
[164/272] Linking CXX executable bin/llvm-sim
[165/272] Linking CXX executable bin/clang-include-fixer
[166/272] Linking CXX executable bin/llvm-modextract
[167/272] Linking CXX executable bin/llvm-objcopy
[168/272] Linking CXX executable bin/llvm-ml
[169/272] Linking CXX executable bin/clang-reorder-fields
[170/272] Linking CXX executable bin/pp-trace
[171/272] Linking CXX executable bin/llvm-pdbutil
[172/272] Linking CXX executable bin/llvm-size
[173/272] Linking CXX executable bin/tool-template
[174/272] Linking CXX executable bin/llvm-libtool-darwin
[175/272] Linking CXX executable bin/llvm-mca
[176/272] Linking CXX executable bin/llvm-tli-checker
[177/272] Linking CXX executable bin/clang-extdef-mapping
[178/272] Linking CXX executable bin/clang-query
[179/272] Linking CXX executable bin/clang-change-namespace
[180/272] Linking CXX executable bin/yaml2obj
[181/272] Linking CXX executable bin/clang-move
[182/272] Linking CXX executable bin/llvm-rtdyld
[183/272] Linking CXX executable bin/clang-refactor
[184/272] Linking CXX executable bin/clang-doc
[185/272] Linking CXX executable bin/llvm-readobj
[186/272] Linking CXX executable bin/sancov
[187/272] Linking CXX executable bin/obj2yaml
[188/272] Linking CXX executable bin/modularize
[189/272] Linking CXX executable bin/clang-include-cleaner
[190/272] Linking CXX executable bin/llvm-symbolizer
[191/272] Linking CXX executable bin/llvm-xray
[192/272] Linking CXX executable bin/verify-uselistorder
[193/272] Linking CXX executable bin/sanstats

```

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