x/build: upgrade libc on our LUCI machine images to enable newer versions of clang

[mknyszek]

I tried to set up a clang builder for 16.0.4, but ran into errors like:

        ../../../../cache/tools/clang/bin/clang: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.34' not found (required by ../../../../cache/tools/clang/bin/clang)
        ../../../../cache/tools/clang/bin/clang: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.32' not found (required by ../../../../cache/tools/clang/bin/clang)
        ../../../../cache/tools/clang/bin/clang: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.33' not found (required by ../../../../cache/tools/clang/bin/clang)
        ../../../../cache/tools/clang/bin/clang: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.30' not found (required by ../../../../cache/tools/clang/bin/clang)
        ../../../../cache/tools/clang/bin/clang: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.29' not found (required by ../../../../cache/tools/clang/bin/clang)
        ../../../../cache/tools/clang/bin/clang: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `CXXABI_1.3.13' not found (required by ../../../../cache/tools/clang/bin/clang)

Turns out our libc is just too old on those builders. 15.0.4 works fine, so I put that in CIPD and renamed the builders. This issue tracks upgrading our machine images so we can build against newer versions of clang.

[mknyszek]

This issue is blocking #64563.