Remove AOT (#5340)

* make `jit` mode the default when no mode is specified

* unify JIT and AOT codepaths

* ensure `Object.entries` on undefined doesn't break

It could be that sometimes you don't have values in your config (e.g.: `presets: []`), this in turn will break some plugins where we assume we have a value.

* drop AOT specific tests

These tests are all covered by JIT mode already and were AOT specific.

* simplify tests, and add a few

Some of the tests were written for AOT specifically, some were missing. We also updated the way we write those tests, essentially making Tailwind a blackbox, by testing against the final output.
Now that JIT mode is the default, this is super fast because we only generate what is used, instead of partially testing in a 3MB file or building it all, then purging.

* add some todo's to make sure we warn in a few cases

* make `darkMode: 'media'`, the default

This also includes moving dark mode tests to its own dedicated file.

* remove PostCSS 7 compat mode

* update CLI to be JIT-first

* fix integration tests

This is not a _real_ fix, but it does solve the broken test for now.

* warn when using @responsive or @variants

* remove the JIT preview warning

* remove AOT-only code paths

* remove all `mode: 'jit'` blocks

Also remove `variants: {}` since they are not useful in `JIT` mode
anymore.

* drop unused dependencies

* rename `purge` to `content`

* remove static CDN builds

* mark `--purge` as deprecated in the CLI

This will still work, but a warning will be printed and it won't show up
in the `--help` output.

* cleanup nesting plugin

We don't have to duplicate it anymore since there is no PostCSS 7
version anymore.

* make sure integration tests run in band

* cleanup folder structure

* make sure nesting folder is available

* simplify resolving of purge/content information

tests/plugins/fontSize.test.js

@@ -8,8 +8,17 @@ function run(input, config = {}) {
   })
 }
 
+function css(templates) {
+  return templates.join('')
+}
+
+function html(templates) {
+  return templates.join('')
+}
+
 test('font-size utilities can include a default line-height', () => {
   const config = {
+    content: [{ raw: html`<div class="text-sm text-md text-lg"></div>` }],
     theme: {
       fontSize: {
         sm: '12px',
@@ -24,16 +33,25 @@ test('font-size utilities can include a default line-height', () => {
   }
 
   return run('@tailwind utilities', config).then((result) => {
-    expect(result.css).toMatchCss(`
-     .text-sm { font-size: 12px }
-     .text-md { font-size: 16px; line-height: 24px }
-     .text-lg { font-size: 20px; line-height: 28px }
+    expect(result.css).toMatchCss(css`
+      .text-sm {
+        font-size: 12px;
+      }
+      .text-md {
+        font-size: 16px;
+        line-height: 24px;
+      }
+      .text-lg {
+        font-size: 20px;
+        line-height: 28px;
+      }
     `)
   })
 })
 
 test('font-size utilities can include a default letter-spacing', () => {
   const config = {
+    content: [{ raw: html`<div class="text-sm text-md text-lg"></div>` }],
     theme: {
       fontSize: {
         sm: '12px',
@@ -48,16 +66,25 @@ test('font-size utilities can include a default letter-spacing', () => {
   }
 
   return run('@tailwind utilities', config).then((result) => {
-    expect(result.css).toMatchCss(`
-     .text-sm { font-size: 12px }
-     .text-md { font-size: 16px; letter-spacing: -0.01em }
-     .text-lg { font-size: 20px; letter-spacing: -0.02em }
+    expect(result.css).toMatchCss(css`
+      .text-sm {
+        font-size: 12px;
+      }
+      .text-md {
+        font-size: 16px;
+        letter-spacing: -0.01em;
+      }
+      .text-lg {
+        font-size: 20px;
+        letter-spacing: -0.02em;
+      }
     `)
   })
 })
 
 test('font-size utilities can include a default line-height and letter-spacing', () => {
   const config = {
+    content: [{ raw: html`<div class="text-sm text-md text-lg"></div>` }],
     theme: {
       fontSize: {
         sm: '12px',
@@ -72,10 +99,20 @@ test('font-size utilities can include a default line-height and letter-spacing',
   }
 
   return run('@tailwind utilities', config).then((result) => {
-    expect(result.css).toMatchCss(`
-     .text-sm { font-size: 12px }
-     .text-md { font-size: 16px; line-height: 24px; letter-spacing: -0.01em }
-     .text-lg { font-size: 20px; line-height: 28px; letter-spacing: -0.02em }
+    expect(result.css).toMatchCss(css`
+      .text-sm {
+        font-size: 12px;
+      }
+      .text-md {
+        font-size: 16px;
+        line-height: 24px;
+        letter-spacing: -0.01em;
+      }
+      .text-lg {
+        font-size: 20px;
+        line-height: 28px;
+        letter-spacing: -0.02em;
+      }
     `)
   })
 })