chore: build webworkers separately

Author: achingbrain

.travis.yml

@@ -35,13 +35,25 @@ jobs:
       name: chrome
       addons:
         chrome: stable
-      script: npx aegir test -t browser -t webworker
+      script: npx aegir test -t browser
+
+    - stage: test
+      name: chrome webworker
+      addons:
+        chrome: stable
+      script: npx aegir test -t webworker
 
     - stage: test
       name: firefox
       addons:
         firefox: latest
-      script: npx aegir test -t browser -t webworker -- --browsers FirefoxHeadless
+      script: npx aegir test -t browser -- --browsers FirefoxHeadless
+
+    - stage: test
+      name: firefox webworker
+      addons:
+        firefox: latest
+      script: npx aegir test -t webworker -- --browsers FirefoxHeadless
 
     - stage: test
       name: electron-main