[dev.unified] test: change Unicode file/package name to use characters not translated by macOS.
In filenames, macOS translates Ä (U+00c4, c3 84) to Ä (U+0041 U+0308, 41 cc 88).
This causes problems for run.go's crude rules for testing the compiler.
Fixes #53954.
Change-Id: I850421cbf07e022ca5ff8122e0fb4e80deb55adf
Reviewed-on: https://go-review.googlesource.com/c/go/+/418334
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>