[CI] Upgrade to clang-22 in libc fullbuild tests

[krishna2803]

We need to upgrade to clang-22 in the libc github CI fullbuild once the apt sources are fixed.

ref: #149877, #150246.

[llvmbot]

@llvm/issue-subscribers-libc

Author: Krishna Pandey (krishna2803)

We need to upgrade to clang-22 in the libc github CI fullbuild once the apt sources are fixed.

ref: #149877, #150246.

[llvmbot]

@llvm/issue-subscribers-infrastructure

Author: Krishna Pandey (krishna2803)

We need to upgrade to clang-22 in the libc github CI fullbuild once the apt sources are fixed.

ref: #149877, #150246.