Don't handle preflight separately in corePlugins

If we do, we have to handle disabling/custom configuration separately too, which we don't want.

This really suggests I should prioritize adding a more black-box level test for this part of the codebase.

src/corePlugins.js

@@ -53,7 +53,7 @@ import zIndex from './plugins/zIndex'
 import _ from 'lodash'
 import configurePlugins from './util/configurePlugins'
 
-function loadUtilityPlugins({ theme, variants, corePlugins: userCorePluginConfig }, plugins) {
+function loadPlugins({ theme, variants, corePlugins }, plugins) {
   const defaultCorePluginConfig = _.fromPairs(
     Object.keys(plugins).map(plugin => [
       plugin,
@@ -64,63 +64,61 @@ function loadUtilityPlugins({ theme, variants, corePlugins: userCorePluginConfig
     ])
   )
 
-  return configurePlugins(plugins, userCorePluginConfig, defaultCorePluginConfig)
+  return configurePlugins(plugins, corePlugins, defaultCorePluginConfig)
 }
 
 export default function(config) {
-  return [
-    preflight(),
-    ...loadUtilityPlugins(config, {
-      lists,
-      appearance,
-      backgroundAttachment,
-      backgroundColors,
-      backgroundPosition,
-      backgroundRepeat,
-      backgroundSize,
-      borderCollapse,
-      borderColors,
-      borderRadius,
-      borderStyle,
-      borderWidths,
-      cursor,
-      display,
-      flexbox,
-      float,
-      fonts,
-      fontWeights,
-      height,
-      leading,
-      margin,
-      maxHeight,
-      maxWidth,
-      minHeight,
-      minWidth,
-      negativeMargin,
-      objectFit,
-      objectPosition,
-      opacity,
-      outline,
-      overflow,
-      padding,
-      pointerEvents,
-      position,
-      resize,
-      shadows,
-      svgFill,
-      svgStroke,
-      tableLayout,
-      textAlign,
-      textColors,
-      textSizes,
-      textStyle,
-      tracking,
-      userSelect,
-      verticalAlign,
-      visibility,
-      whitespace,
-      width,
-      zIndex,
-    }),
-  ]
+  return loadPlugins(config, {
+    preflight,
+    lists,
+    appearance,
+    backgroundAttachment,
+    backgroundColors,
+    backgroundPosition,
+    backgroundRepeat,
+    backgroundSize,
+    borderCollapse,
+    borderColors,
+    borderRadius,
+    borderStyle,
+    borderWidths,
+    cursor,
+    display,
+    flexbox,
+    float,
+    fonts,
+    fontWeights,
+    height,
+    leading,
+    margin,
+    maxHeight,
+    maxWidth,
+    minHeight,
+    minWidth,
+    negativeMargin,
+    objectFit,
+    objectPosition,
+    opacity,
+    outline,
+    overflow,
+    padding,
+    pointerEvents,
+    position,
+    resize,
+    shadows,
+    svgFill,
+    svgStroke,
+    tableLayout,
+    textAlign,
+    textColors,
+    textSizes,
+    textStyle,
+    tracking,
+    userSelect,
+    verticalAlign,
+    visibility,
+    whitespace,
+    width,
+    zIndex,
+  })
 }