chore(build): Remove build products from repository

Remove *_compressed.js* and msg/js/* from the blockly repository.
Also remove the now-obsolete checkinBuilt gulp task.

scripts/gulpfiles/build_tasks.js

@@ -704,20 +704,6 @@ function buildAdvancedCompilationTest() {
       .pipe(gulp.dest('./tests/compile/'));
 }
 
-/**
- * This task copies built files from BUILD_DIR and RELEASE_DIR back to
- * the repository so they can be committed to git.
- *
- * Prerequisite: buildCompiled, buildLangfiles.
- */
-function checkinBuilt() {
-  return gulp.src([
-    `${RELEASE_DIR}/*_compressed.js`,
-    `${RELEASE_DIR}/*_compressed.js.map`,
-    // `${BUILD_DIR}/msg/*.js`,  // Temporarily disabled (base mismatch).
-  ], {base: RELEASE_DIR}).pipe(gulp.dest('.'));
-}
-
 /**
  * This task cleans the build directory (by deleting it).
  */
@@ -758,6 +744,3 @@ exports.buildAdvancedCompilationTest =
 
 // Targets intended only for invocation by scripts; may omit prerequisites.
 exports.onlyBuildAdvancedCompilationTest = buildAdvancedCompilationTest;
-
-// Legacy target, to be deleted.
-exports.checkin = gulp.series(exports.build, checkinBuilt);

scripts/gulpfiles/release_tasks.js

@@ -13,7 +13,6 @@ var fs = require('fs');
 var gulp = require('gulp');
 var readlineSync = require('readline-sync');
 
-var buildTasks = require('./build_tasks');
 var gitTasks = require('./git_tasks');
 var packageTasks = require('./package_tasks');
 var {getPackageJson} = require('./helper_tasks');
@@ -171,7 +170,6 @@ const recompileDevelop = gulp.series(
   gitTasks.createRebuildBranch,
   updateVersionPrompt,
   packageTasks.package,  // Does clean + build.
-  buildTasks.checkin,
   gitTasks.pushRebuildBranch
   );