fix(cfl): align batch workflow with PR workflow — drop UBSan, guard SARIF

cflite_batch.yml had the same issues as cflite_pr.yml:
- 'undefined' sanitizer in matrix causes a build-time Rust error
  (no -Z sanitizer=undefined) and bad_build_check failures
- upload-sarif with bare if:always() fails when no crashes are found

Apply the same fixes: matrix: [address] only, hashFiles() guard.

https://claude.ai/code/session_01EJLZKDtcF1RGdKx6TcUTQG

Author: claude

.github/workflows/cflite_batch.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        sanitizer: [address, undefined]
+        sanitizer: [address]
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
       - uses: google/clusterfuzzlite/actions/build_fuzzers@884713a6c30a92e5e8544c39945cd7cb630abcd1 # v1
@@ -25,6 +25,6 @@ jobs:
           mode: batch
           output-sarif: true
       - uses: github/codeql-action/upload-sarif@662472033e021d55d94146f66f6058822b0b39fd # v3
-        if: always()
+        if: always() && hashFiles('vulnerabilities.sarif') != ''
         with:
           sarif_file: vulnerabilities.sarif