Typescript plugin doesn't emit latest assets on rollup when watchMode is false

[gbaron]

• Rollup Plugin Name: @rollup/plugin-typescript
• Rollup Plugin Version: 9.0.2
• Rollup Version: 3.4.0
• Operating System (or Browser): Mac OS
• Node Version: 16.17.0
• Link to reproduction (⚠️ read below): https://github.com/gbaron/rollup-ts-issue

Expected Behavior

The emitted code should match the typescript compiled result of the source file

Actual Behavior

The emitted code doesn't match the source.

Additional Information

Scenario:

1. Initialize @rollup/plugin-typescript once.
2. Use the plugin in a rollup configuration.
3. Invoke rollup.rollup(...) on 'x.ts' and then bundle.generate to generate JS code.
4. Mutate `x.ts'
5. Invoke rollup.rollup(...) on 'x.ts' and then bundle.generate again.

Result: The same JS code will be generated after steps 3 and 5.
Expected: After step 5, the JS code should be different and match the updated x.ts.

Note: Although watchMode is false. The expectation is that invoking rollup.rollup(...) will always generate up-to-date results.

[gbaron]

@shellscape I've made a minor PR to fix this issue.