Fix loom.accessWidener being a read-only property in Kotlin (#447)

* Re-enable Kotlin test because the related bug has been fixed

* Fix loom.accessWidener being a read-only property in Kotlin

* Remove Kotlin test exclusions

.github/workflows/test-push.yml

@@ -45,9 +45,6 @@ jobs:
       matrix:
         java: [jdk16]
         test: ${{ fromJson(needs.prepare_test_matrix.outputs.matrix) }}
-        exclude:
-          - java: jdk16
-            test: net.fabricmc.loom.test.integration.KotlinTest
 
     runs-on: ubuntu-20.04
     container:
@@ -74,9 +71,6 @@ jobs:
       matrix:
         java: [16]
         test: ${{ fromJson(needs.prepare_test_matrix.outputs.matrix) }}
-        exclude:
-          - java: 16
-            test: net.fabricmc.loom.test.integration.KotlinTest
 
     runs-on: windows-2019