core: Fix ignore_changes = all

The initial rework of this function to support traversals didn't correctly
handle the "all" case, due to a logic error where the ignoreAll branch
could be visited only if ignoreChanges were non-empty, but yet the two
are mutually exclusive in practice.

Now we process ignoreAll separately from ignoreChanges, and invert the
two loops so that we will visit all attributes regardless of what is
in the ignoreChanges slice.

terraform/eval_diff.go

@@ -254,10 +254,14 @@ func (n *EvalDiff) processIgnoreChanges(diff *InstanceDiff) error {
 
 	// get the complete set of keys we want to ignore
 	ignorableAttrKeys := make(map[string]bool)
-	for _, ignoredTraversal := range ignoreChanges {
-		ignoredKey := legacyFlatmapKeyForTraversal(ignoredTraversal)
-		for k := range attrs {
-			if ignoreAll || strings.HasPrefix(k, ignoredKey) {
+	for k := range attrs {
+		if ignoreAll {
+			ignorableAttrKeys[k] = true
+			continue
+		}
+		for _, ignoredTraversal := range ignoreChanges {
+			ignoredKey := legacyFlatmapKeyForTraversal(ignoredTraversal)
+			if k == ignoredKey || strings.HasPrefix(k, ignoredKey+".") {
 				ignorableAttrKeys[k] = true
 			}
 		}