Build the stage0 with optimizations

Swift is a tad slow when it's not built with optimizations.

Author: etcwilde

utils/build-presets.ini

@@ -1006,6 +1006,7 @@ reconfigure
 [preset: buildbot_linux,no_test,stage0]
 build-subdir=buildbot_linux/stage0
 install-destdir=%(install_destdir)s
+release
 skip-build-benchmarks
 skip-test-cmark
 skip-early-swift-driver