[clangd] Avoid "expected one compiler job" by picking the first eligible job.

This happens in createInvocationWithCommandLine but only clangd currently passes
ShouldRecoverOnErorrs (sic).

One cause of this (with correct command) is several -arch arguments for mac
multi-arch support.

Fixes https://github.com/clangd/clangd/issues/827

Differential Revision: https://reviews.llvm.org/D107632