fix(tests): Fix compressed mode loading (#7178)

Due to errors in PRs #7171 and 7173 (and the author's failure to do
enough local testing before submitting those PRs), compressed mode
loading was broken in the playgrounds.  Fix this by:

- Fix a typo in bootstrap.js ("Blocky" -> "Blockly").
- Updating the chunks definitions build_tasks.js to use the new
  variables we expect to contain generator exports objects.

scripts/gulpfiles/build_tasks.js

@@ -111,35 +111,35 @@ const chunks = [
   {
     name: 'javascript',
     entry: path.join(TSC_OUTPUT_DIR, 'generators', 'javascript', 'all.js'),
-    exports: 'module$build$src$generators$javascript$all',
+    exports: 'module$build$src$generators$javascript',
     scriptExport: 'javascript',
     scriptNamedExports: {'Blockly.Javascript': 'javascriptGenerator'},
   },
   {
     name: 'python',
     entry: path.join(TSC_OUTPUT_DIR, 'generators', 'python', 'all.js'),
-    exports: 'module$build$src$generators$python$all',
+    exports: 'module$build$src$generators$python',
     scriptExport: 'python',
     scriptNamedExports: {'Blockly.Python': 'pythonGenerator'},
   },
   {
     name: 'php',
     entry: path.join(TSC_OUTPUT_DIR, 'generators', 'php', 'all.js'),
-    exports: 'module$build$src$generators$php$all',
+    exports: 'module$build$src$generators$php',
     scriptExport: 'php',
     scriptNamedExports: {'Blockly.PHP': 'phpGenerator'},
   },
   {
     name: 'lua',
     entry: path.join(TSC_OUTPUT_DIR, 'generators', 'lua', 'all.js'),
-    exports: 'module$build$src$generators$lua$all',
+    exports: 'module$build$src$generators$lua',
     scriptExport: 'lua',
     scriptNameExports: {'Blockly.Lua': 'luaGenerator'},
   },
   {
     name: 'dart',
     entry: path.join(TSC_OUTPUT_DIR, 'generators', 'dart', 'all.js'),
-    exports: 'module$build$src$generators$dart$all',
+    exports: 'module$build$src$generators$dart',
     scriptExport: 'dart',
     scriptNameExports: {'Blockly.Dart': 'dartGenerator'},
   }

tests/bootstrap.js

@@ -74,7 +74,7 @@
       {
         id: 'Blockly',
         script: 'dist/blockly_compressed.js',
-        scriptExport: 'Blocky',
+        scriptExport: 'Blockly',
         importAt: 'Blockly',
       },
       {