Improve speed of test_tokenize.StringPrefixTest.test_prefixes

[ericvsmith]

Bug report

Bug description:

It takes about 0.5 seconds to run, because it's doing 127,452 eval statements. It could no doubt be sped up, although I might have to sacrifice some completeness. For example, one simplifying assumption is that all multi-character string prefixes must begin with one of the single-character prefix. I guess it's possible that this won't always be the case, but it seems likely to continue.

CPython versions tested on:

3.15

Operating systems tested on:

Windows

Linked PRs

• gh-134752: Improve speed of test_tokenize.StringPrefixTest.test_prefixes. #134766
• [3.14] gh-134752: Improve speed of test_tokenize.StringPrefixTest.test_prefixes. (GH-134766) #134782