Fix edge case with empty string

Else we add an empty feature and the flag start with
`-enable-ff=,<default-flags>`;

Bug: none
Change-Id: Id2da1598d9826deee2f63d38bdb5dfb761f4b53a
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6468517
Auto-Submit: Nikolay Vitkov <[email protected]>
Reviewed-by: Benedikt Meurer <[email protected]>
Commit-Queue: Benedikt Meurer <[email protected]>
diff --git a/scripts/devtools_build.mjs b/scripts/devtools_build.mjs
index dd7473f..36bdbcc 100644
--- a/scripts/devtools_build.mjs
+++ b/scripts/devtools_build.mjs
@@ -97,6 +97,9 @@
   }
 
   static parse(text) {
+    if (!text) {
+      return [];
+    }
     const features = [];
     for (const str of text.split(',')) {
       const parts = str.split(':');