This code was borked as SlaveComputer is not serializable and we are passing an implicit ref to the outer class.

- I suspect that nobody has ever used this method given the lack of conversion to static inner class required to make it work
Consider actual Jenkins.numExecutors if >0; only replace 0 with 1 (thus 100 slots).
Also, just for completeness, do the same trick for slaves if they happen to have 0 executors:
in case the flyweight task is bound to a label (would not be the case for MatrixProject);
and in case the slave is still online with a Computer (e.g. still has running builds).
Updated comment in POM.
'mvn -Dtest=hudson.maven.MavenProjectTest#testDeleteSetBuildDeletesModuleBuilds test' fails on empty local repo.
~/.m2/repository/org/jvnet/hudson/main/test/multimod/moduleA/1.0-SNAPSHOT/moduleA-1.0-SNAPSHOT.jar was missing; need install goal.
Better to set a local repo so we do not pollute the real repo, and to avoid interaction between tests.
Merge branch 'master' of github.com:jenkinsci/jenkins
Merge branch 'master' into flyweight-master-JENKINS-7291