[Github] Make issue-write workflow support reading from multiple files

This is so that we can read from multiple files emitted by the premerge
workflow.

Reviewers: tstellar, cmtice

Reviewed By: cmtice

Pull Request: llvm/llvm-project#170411

Author: boomanaiden154

.github/workflows/issue-write-test.yaml

@@ -17,10 +17,17 @@ jobs:
     steps:
       - name: Write Comment
         run: |
-          echo '[{"body": "This is a comment for testing the issue write workflow"}]' > comments
+          echo '[{"body": "This is a comment for testing the issue write workflow"}]' > comments-foo
+          echo '[{"body": "This is another comment for testing the issue write workflow that was placed in a separate file"}]' > comments-bar
       - name: Upload Comment
         uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
         with:
-          name: workflow-args
+          name: workflow-args-foo
           path: |
-            comments
+            comments-foo
+      - name: Upload Comment
+        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
+        with:
+          name: workflow-args-bar
+          path: |
+            comments-bar

.github/workflows/issue-write.yml

@@ -47,7 +47,12 @@ jobs:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
             var fs = require('fs');
-            const comments = JSON.parse(fs.readFileSync('./comments'));
+            var comments = []
+            for (local_file of fs.readdirSync('.')) {
+              if (local_file.startsWith("comments")) {
+                comments.push(...JSON.parse(fs.readFileSync(local_file)))
+              }
+            }
             if (!comments || comments.length == 0) {
               return;
             }