classfields tests for eval early errors

# Conflicts:
#	src/class-fields/eval-err-contains-arguments.case
#	src/class-fields/eval-err-contains-supercall-1.case
#	src/class-fields/eval-err-contains-supercall-2.case
#	src/class-fields/eval-err-contains-supercall.case
#	src/class-fields/eval-err-contains-superproperty-1.case
#	src/class-fields/eval-err-contains-superproperty-2.case