Build: upgrade dependencies, including eslint 9.4.0 and uglify 3.7.7

- Sinon is already at the latest version that supports IE9.
- Upgraded uglify to 3.7.7, which is the latest that worked with IE9.
  I tried 3.9.4, which we are using in jquery-migrate, and 3.8.1,
  but there were failures in traversing ("Permission denied" errors).
- Upgraded eslint to version 9, which required some changes.
  Mainly, unused arguments in catch expressions error by default in 9+.
  The config now makes use of `caughtErrorsIgnorePattern`,
  which is set to `"^_"`, the same as unused function params.
- Ignored main branch dist files when switching branches.

Closes gh-5508

3 files changed, 3 insertions, 3 deletions

diff --git a/build/tasks/build.js b/build/tasks/build.js
index a1b69b18e..68c85dc6f 100644
--- a/build/tasks/build.js
+++ b/build/tasks/build.js
@@ -57,7 +57,7 @@ async function readdirRecursive( dir, all = [] ) {
 		files = await fs.readdir( path.join( srcFolder, dir ), {
 			withFileTypes: true
 		} );
-	} catch ( e ) {
+	} catch ( _ ) {
 		return all;
 	}
 	for ( const file of files ) {
diff --git a/build/tasks/compare_size.mjs b/build/tasks/compare_size.mjs
index a94cf42f0..36d8136f8 100644
--- a/build/tasks/compare_size.mjs
+++ b/build/tasks/compare_size.mjs
@@ -36,7 +36,7 @@ async function getCache( loc ) {
 	try {
 		const contents = await fs.readFile( loc, "utf8" );
 		cache = JSON.parse( contents );
-	} catch ( err ) {
+	} catch ( _ ) {
 		return {};
 	}
 
diff --git a/build/tasks/promises_aplus_tests.js b/build/tasks/promises_aplus_tests.js
index f8deaa6a0..4624b3a9a 100644
--- a/build/tasks/promises_aplus_tests.js
+++ b/build/tasks/promises_aplus_tests.js
@@ -24,7 +24,7 @@ async function runTests() {
 		spawn(
 			command,
 			[ test ].concat( args ),
-			{ stdio: "inherit" }
+			{ shell: true, stdio: "inherit" }
 		);
 	} );
 }