Reactivate parts of test for variable encoding#1830

ax3l merged 1 commit intoopenPMD:devopenPMD/openPMD-api:devfrom

franzpoeschel:fix-read-variablebased-randomaccess-testfranzpoeschel/openPMD-api:fix-read-variablebased-randomaccess-testCopy head branch name to clipboard