Isolate scalar quoting oddities to one test set.

The apimachinery code path, in its final marshalling
for output, calls Marshall

  https://github.com/go-yaml/yaml/blob/v2/yaml.go#L199

This code path (via apimachinery Unstructured types)
has no JSON schema tags

  https://yaml.org/spec/1.2/spec.html#id2803311

so it adds quotes to values that smell like
booleans and ints (e.g. `false` becomes `"false"`).

The kyaml code path, OTOH, uses such tags,
so generally does not quote ints and booleans.

This PR isolates this difference in behavior to
one set of tests (using data fields in configmaps
in api/krusty/configmaps_test.go) so that
they don't confuse other tests that cover
completely different behaviors.

api/krusty/namespacedgenerators_test.go

@@ -80,7 +80,7 @@ namespace: base
 configMapGenerator:
 - name: testCase
   literals:
-    - base=true
+    - base=apple
 `)
 	th.WriteK("/app/overlay", `
 resources:
@@ -92,17 +92,17 @@ configMapGenerator:
   - name: testCase
     behavior: merge
     literals:
-      - overlay=true
+      - overlay=peach
 `)
 	m := th.Run("/app/overlay", th.MakeDefaultOptions())
 	th.AssertActualEqualsExpected(m, `
 apiVersion: v1
 data:
-  base: "true"
-  overlay: "true"
+  base: apple
+  overlay: peach
 kind: ConfigMap
 metadata:
-  name: testCase-bcbmmg48hd
+  name: testCase-gmfch8gkbt
   namespace: overlay
 `)
 }