tests: re-organize autofixing unit tests

This change:
- Changes test data naming convention to be lexicographically sortable
  and have input and expected data side-by-side.
- Executes each test case in a separate run.

core/pkg/fixhandler/testdata/hybrids/tc-01-00-input.yaml

@@ -16,4 +16,4 @@ spec:
   - name: nginx_container
     image: nginx
     securityContext:
-      runAsRoot: true
+      runAsRoot: true

core/pkg/fixhandler/testdata/hybrids/tc-01-01-expected.yaml

@@ -16,4 +16,4 @@ spec:
   - name: nginx_container
     image: nginx
   securityContext:
-    runAsRoot: false
+    runAsRoot: false

core/pkg/fixhandler/testdata/inserts/tc-01-00-input.yaml

@@ -9,4 +9,4 @@ metadata:
 spec:
   containers:
   - name: nginx_container
-    image: nginx
+    image: nginx

core/pkg/fixhandler/testdata/inserts/tc-01-01-expected.yaml

@@ -11,4 +11,4 @@ spec:
   - name: nginx_container
     image: nginx
     securityContext:
-      allowPrivilegeEscalation: false
+      allowPrivilegeEscalation: false