command: Fix all of the "taint" command tests

Most of this is just updates to allow for the fact that we now always save
the provider address as part of resource state, whereas before it was only
saved conditionally.

This also updates TestTaint_module for the intentional change that it now
expects a child module to be specified using normal resource address
syntax, rather than as a separate -module option.

command/taint_test.go

@@ -379,9 +379,8 @@ func TestTaint_module(t *testing.T) {
 	}
 
 	args := []string{
-		"-module=child",
 		"-state", statePath,
-		"test_instance.blah",
+		"module.child.test_instance.blah",
 	}
 	if code := c.Run(args); code != 0 {
 		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
@@ -393,18 +392,22 @@ func TestTaint_module(t *testing.T) {
 const testTaintStr = `
 test_instance.foo: (tainted)
   ID = bar
+  provider = provider.test
 `
 
 const testTaintDefaultStr = `
 test_instance.foo:
   ID = bar
+  provider = provider.test
 `
 
 const testTaintModuleStr = `
 test_instance.foo:
   ID = bar
+  provider = provider.test
 
 module.child:
   test_instance.blah: (tainted)
     ID = blah
+    provider = provider.test
 `