Capture/Replay: Limit number of compile processes based on load When replaying, for each batch a limited number of compile processes is launched, but no all-over limit is set, so that on computers with a low processor count and/or limited working memory the machine may become un-responsive. Therefore, tell ninja to not spawn new processes when the load is larger than the number of available processors. Bug: angleproject:6078 Change-Id: I9982a139ef2346d0cf25fbd510c7aff038e48071 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2976658 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Cody Northrop <cnorthrop@google.com> Commit-Queue: Gert Wollny <gert.wollny@collabora.com>