Error replacing statement that shares line with another statement

[ghost]

TypeScript Version: master

Code

See refactorConvertToEs6Module_export_referenced.ts (as of #22361)

Expected behavior:

_z; z;

Actual behavior:

_z  z;

[ghost]

This isn't due to the statements sharing the same line, but because refactorConvertToEs6Module replaces the whole function, then tries replacing part of the function. We should have been catching this error in textChanges but weren't due to a bug.