The build no longer works for Kotlin < 1.8: We get
error: class 'org.jetbrains.kotlin.ir.IrElement' was compiled
with an incompatible version of Kotlin. The binary version
of its metadata is 1.8.0, expected version is 1.6.0.
The second invocation was failing with a "file already exists" error.
I've also added a checkTrapIdentical flag, which is enabled for now.
This means that if 2 invocations write the same TRAP file, we will awrn
if they are not identical. It may be that this produces false positives,
but we can look at that if it happens.
