fuzzer: add special-case for multi-line EOF TokenError (#1991)

* Add special-case for multi-line EOF TokenError under Python3.7

* Update conditional check to correspond to original issue description (and include issue hyperlink)

* Add warning and hint regarding replaying the fuzzer code generation

* Include code review suggestion (with modifications for this to follow)

Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com>

* Remove Python version check, since this issue does exist across more recent Python versions than 3.7

* Update explanatory comment

* Add clarification for potentially-ambiguous blib2to3 import

* Update explanatory comment

* Bring comment into consistent format with previous comment

* Revert "Add clarification for potentially-ambiguous blib2to3 import"

This reverts commit 357b7cc03bdb19dd924f1accd428352f4bb44e5c.

Co-authored-by: Zac Hatfield-Dodds <zac.hatfield.dodds@gmail.com>