[Github][CI] Make premerge upload results on Linux and Windows (llvm#170414)

Now that the issue-write workflow can support writing comments from
multiple files, make the premerge workflow write out comments from both
x86_64 Linux and Windows. AArch64 Linux right now is left out as the
premerge advisor does not currently support it.

Author: boomanaiden154

.ci/premerge_advisor_explain.py

@@ -129,7 +129,8 @@ def main(
         # If the job succeeds and there is not an existing comment, we
         # should not write one to reduce noise.
         comments = []
-    with open("comments", "w") as comment_file_handle:
+    comments_file_name = f"comments-{platform.system()}-{platform.machine()}"
+    with open(comments_file_name, "w") as comment_file_handle:
         json.dump(comments, comment_file_handle)
 
 

.github/workflows/premerge.yaml

@@ -124,9 +124,9 @@ jobs:
         if: ${{ always() && !startsWith(matrix.runs-on, 'depot-ubuntu-24.04-arm') }}
         continue-on-error: true
         with:
-          name: workflow-args
+          name: workflow-args-x86-linux
           path: |
-            comments
+            comments-Linux-x86_64
 
   premerge-checks-windows:
     name: Build and Test Windows
@@ -185,6 +185,14 @@ jobs:
           path: artifacts/
           retention-days: 5
           include-hidden-files: 'true'
+      - name: Upload Comment
+        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
+        if: always()
+        continue-on-error: true
+        with:
+          name: workflow-args-windows
+          path: |
+            comments-Windows-x86_64
 
   premerge-check-macos:
     name: MacOS Premerge Checks