llvm-project

6a45697f - [CI] Downgrade to clang-20 for libc fullbuild (#150246)

[CI] Downgrade to clang-20 for libc fullbuild (#150246) To be reverted when llvm-21 issues are resolved with the precommit CIs. Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>