Class Fields: minor updates to existing templates to improve output source

src/class-fields/eval-err-contains-newtarget.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/private-names.case

...s/productions/cls-decl-after-same-line-async-gen.template

...roductions/cls-decl-after-same-line-async-method.template

...-fields/productions/cls-decl-after-same-line-gen.template

...elds/productions/cls-decl-after-same-line-method.template

...ctions/cls-decl-after-same-line-static-async-gen.template

...ons/cls-decl-after-same-line-static-async-method.template

.../productions/cls-decl-after-same-line-static-gen.template

...oductions/cls-decl-after-same-line-static-method.template

...fields/productions/cls-decl-multiple-definitions.template

...roductions/cls-decl-multiple-stacked-definitions.template

...ields/productions/cls-decl-new-no-sc-line-method.template

...ields/productions/cls-decl-new-sc-line-generator.template

...s-fields/productions/cls-decl-new-sc-line-method.template

...-fields/productions/cls-decl-regular-definitions.template