cmd/go: run tests that require package build IDs

    
    These tests used to be disabled in the gofrontend since the go tool
    didn't support build IDs for the gofrontend. It does now, so enable
    the tests again.
    
    Reviewed-on: https://go-review.googlesource.com/111098

From-SVN: r259875

gcc/go/gofrontend/MERGE

-cef3d77a3dc0207454aabdc3ef0e8f9a0ffdf32e
+e367bffce3d2c49b456fdf41ab097bded2bcbc3b
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/cmd/go/go_test.go

@@ -1034,7 +1034,6 @@ func TestGoInstallRebuildsStalePackagesInOtherGOPATH(t *testing.T) {
 }
 
 func TestGoInstallDetectsRemovedFiles(t *testing.T) {
-	skipIfGccgo(t, "gccgo does not yet support package build IDs")
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.parallel()
@@ -1104,7 +1103,6 @@ func TestGoInstallErrorOnCrossCompileToBin(t *testing.T) {
 }
 
 func TestGoInstallDetectsRemovedFilesInPackageMain(t *testing.T) {
-	skipIfGccgo(t, "gccgo does not yet support package build IDs")
 	tooSlow(t)
 	tg := testgo(t)
 	defer tg.cleanup()