Fix Map assertions with babel transform-runtime

[landeqiming666]

Summary

• generate value references for global built-ins when converting class-property annotations, so Map can be rewritten consistently by babel-plugin-transform-runtime
• accept real Map instances created outside the current realm, which avoids an instanceof mismatch when the runtime constructor differs
• add focused transform and runtime regressions for the class-property path

This keeps the conversion change scoped to class-property decorators and covers both the generated reference and the runtime predicate path.

Fixes #177

Validation

• yarn --cwd packages/babel-plugin-flow-runtime build
• yarn --cwd packages/babel-plugin-flow-runtime test (240 passing)
• yarn --cwd packages/flow-runtime test (169 passing)
• targeted lint for all changed source and test files (no errors)
• git diff --check

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IssueHunt Summary

Referenced issues

This pull request has been submitted to:

• #177: Map class property assertion fails when using babel-plugin-transform-runtime

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[landeqiming666]

Hi, a brief follow-up on this PR. It remains clean and mergeable. The patch targets the class-property Map case under babel transform-runtime and includes end-to-end transform fixtures. Happy to adjust the transform scope or tests.