cmd/go: convert TestRelativeGOBINFail to script framework

Part of converting all tests to script framework to improve
test parallelism.

Updates #36320
Updates #17751

Change-Id: I1cb3e2e28700b05b08933f4e24cd996268c1f163
Reviewed-on: https://go-review.googlesource.com/c/go/+/214428
Reviewed-by: Jay Conrod <jayconrod@google.com>

src/cmd/go/go_test.go

@@ -1138,16 +1138,6 @@ func TestMSanAndRaceRequireCgo(t *testing.T) {
 	}
 }
 
-func TestRelativeGOBINFail(t *testing.T) {
-	tg := testgo(t)
-	defer tg.cleanup()
-	tg.tempFile("triv.go", `package main; func main() {}`)
-	tg.setenv("GOBIN", ".")
-	tg.cd(tg.path("."))
-	tg.runFail("install")
-	tg.grepStderr("cannot install, GOBIN must be an absolute path", "go install must fail if $GOBIN is a relative path")
-}
-
 func TestPackageMainTestCompilerFlags(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()

src/cmd/go/testdata/script/install_relative_gobin_fail.txt

@@ -0,0 +1,8 @@
+env GOBIN=.
+! go install
+stderr 'cannot install, GOBIN must be an absolute path'
+
+-- triv.go --
+package main
+
+func main() {}