argumentsToString should never reflect text: 'stuff'

[jglick]

Supersedes #104. @bwalding @imonteroperez

Note that if you were bitten by this issue, you were probably writing your Pipeline script using poor practices to begin with. For example,

def json = sh returnStdout: true, script: 'something-yielding-secret-JSON'
def object = readJSON text: json

can be rewritten as a first step to

def object
try {
  sh 'mkdir -p $WORKSPACE_TMP  && something-yielding-secret-JSON > $WORKSPACE_TMP/secret.json'
  object = readJSON file: "$WORKSPACE_TMP/secret.json"
} finally {
  sh 'rm -f $WORKSPACE_TMP/secret.json'
}

but better still is to never have this secret JSON text pass through Pipeline script at all:

sh 'something-yielding-secret-JSON | something-using-secret-JSON'

(Pipeline does not expect actual secrets to ever be exposed in plain text to Groovy code. withCredentials can be used to inject secrets from Jenkins to a build, but if secrets are produced within the build, there should be no reason for them to be loaded into orchestration logic itself.)