devtool: Build A and B binaries if $do_build is true

If `cmd_test` is instructed to build its own binaries (e.g. being ran
outside of CI), and the environment specifies that A/B-tests should
be ran, then we not only need to build the currently checked out commit
(the "B" revision), but also an "A" binary based on the value of the
`BUILDKITE_PULL_REQUEST_BASE_BRANCH` environment variable.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

tools/devtool

@@ -722,7 +722,12 @@ cmd_test() {
     ensure_devctr
     ensure_build_dir
     ensure_ci_artifacts
-    [ $do_build != 0 ] && cmd_build --release
+    if [ $do_build != 0 ]; then
+      cmd_build --release
+      if [ -n "$BUILDKITE_PULL_REQUEST_BASE_BRANCH" ]; then
+        cmd_build --release --rev "$BUILDKITE_PULL_REQUEST_BASE_BRANCH"
+      fi
+    fi
 
     apply_linux_61_tweaks