fix(ci): test only aarch64-musl in temp workflow — x86_64 already proven

Author: ahmedhesham6

.github/workflows/test-jemalloc-fix.yml

@@ -17,8 +17,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - target: x86_64-unknown-linux-musl
-            runner: ubuntu-latest
           - target: aarch64-unknown-linux-musl
             runner: ubuntu-22.04-arm