it defaults to `panicnil=0`, making `panic(nil)` a run-time error.
Using `panicnil=1` restores the behavior of Go 1.20 and earlier.

When compiling a work module or workspace that declares
an older Go version, the Go toolchain amends its defaults
to match that older Go version as closely as possible.
For example, when a Go 1.21 toolchain compiles a program,
if the work module's `go.mod` or the workspace's `go.work`

pkg testing, func MainStart(testDeps, []InternalTest, []InternalBenchmark, []InternalExample) *M
pkg testing, func RegisterCover(Cover)
pkg text/scanner, const GoTokens = 1012
pkg text/template/parse, type DotNode bool
pkg text/template/parse, type Node interface { Copy, String, Type }
pkg unicode, const Version = "10.0.0"