If a freestyle job has 'system' jdk set, behaviour changes depending on how many installers are present.

To reproduce:

• Ensure only one jdk installer is configured
• Create freestyle job with selected jdk as 'system'
• Ensure job runs on worker node (not controller)
• Add 'execute windows batch command' step to job, which runs 'java -version'
• Run job
• Add second configured jdk installer to global tools configuration
• Re-run job

Observed results:

• First run of job succeeds and displays jdk information
• Second run fails, which java executable not found in path