Make sure ninja keeps going after errors

Language services builds are usually executed in a non-building state of the codebase as the user is actively editing the code.

This change ensures we can build as many dependencies as possible for language services by ninja.

Note that this doesn't change the error-limit for soong itself, i.e. we can still fail-early if we encounter errors while generating ninja files.

Change-Id: I594e2ae4591d2e75db082486f28f705833ceb4a8