Ignore incompatible NIR files instead of crashing

[WojciechMazur]

Related to munit 1.0.0-M11 release - lampepfl/gears#64 (comment) - in this release probably some garbage file generated using 0.4.x where packaged together with NIR files generated for 0.5.x.
The one identified file that could have contained old version of NIR was from Reflectively Instantiated class - in the 0.5.x the symbol names of them are fixed, previously they were create non-standard name partially based on mangle name of the owner class. Because build tool does not clean the target/scala-X/classes directory this single file could have survived the compilation after upgrade to 0.5.0 without override as there would be no file generated with that name in 0.5.x.

Even though this issue was related to contamination of release build for munit, we should be able to prepare toolchain for this kind of issues. We should ignore NIR files that have incompatible format, instead of crashing build using exception. Probably this file was only read when scanning for NIR files to gather required information and it would not be used when class loading.

Steps to reproduce:

1. git clone https://github.com/scalameta/munit -b v1.0.0-M1
2. sbt +munitNative/compile
3. Update version of Scala Native plugin from 0.4.x to 0.5.0
4. sbt +munitNative/publishLocal
5. Try to compile using scala-cli

//> using dep org.scalameta::munit::1.0.0-M11+<data-specific-part>-SNAPSHOT

class MyTests extends munit.FunSuite {
  test("foo") {
    assert(2 + 2 == 4)
  }
}