getType is called a lot, and it just run the same regexp over and over on the same base types. A cache increase its own efficiency by more than 80% for basic types. On a real world application with a lot of components, getType was profiled for 8% of call duration before this patch, and about 0.5% after.
The impact is more limited for smaller applications.

Same as #12123, but against current main branch.

I know this won't be merged, but I abuse test runners, so I validate my patch against latest Vue before using yarn patch

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe: performance improvement

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the main branch for v2.x (or to a previous version branch)
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• All tests are passing: https://github.com/vuejs/vue/blob/dev/.github/CONTRIBUTING.md#development-setup
• New/updated tests are included

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information:

See #12123 for more detail.