fix: use pre-built binary instead of go run in e2e tests (#16236)

Using `go run` inside of a test is fragile, because it means we have to
wait for `go` to compile the binary while also constrained on resources
by the fact that Playwright and coderd are already running. We should
instead compile a coder binary for the current platform before the tests
and use it directly.

.gitignore

@@ -36,6 +36,7 @@ site/.swc
 .gen-golden
 
 # Build
+bin/
 build/
 dist/
 out/