SOLR translator is not defined in standalone.conf. It should be defined in teiid subsystem.
Its on the pushed branch to be pulled by productization, so it should be in the ER1 build.
The Teiid tag that's being pulled for ER1 is: 8.7.0.4-prod-ipv6.1 And, Filip, I think you meant to say standalone.xml, after the installation is performed. Also, to confirm its not an installation issue, be sure to check cli_scripts/teiid-standalone-mode-install.cli (but its not there, I checked).