It affected the changed test in the following way: "strict metadata
version semantics" is a flag which is written to the .kotlin_module file
between the version and the protobuf data, see `ModuleMapping:73`. But
flags are written only for Kotlin 1.4+, i.e. if `isKotlin1Dot4OrLater`
returns true. So in the test, the flag was not written, thus we did not
detect that the module actually has incompatible metadata, and thus
incorrectly did not report an error.
It also has an effect that version requirements for nested classes will
now be written correctly to protobuf with metadata version 2.0+.
Alexander Udalov
25c600c556