With the main source sets now compiling on both platforms the native
test compilation finally ran, and it rejected a handful of test-side
forms the jvm toolchain silently accepts.
Backtick test names are mapped onto native symbols, where a comma is
an illegal character, so three names drop the comma; the wording keeps
the same meaning. java.lang.Math.PI has no common analogue and becomes
kotlin.math.PI, matching the already-qualified kotlin.math.sin call on
the same line. String.toByteArray() is jvm-only, and the byte-length
assertion for the APRS line budget switches to encodeToByteArray(),
the same replacement the production sources went through.