Problem

SERVER-136176 moved s390x release builds to ARM64-hosted cross compilation, but remaining Bazel build tasks on v9.0 and older branches still compile and link on native zSeries hosts. Extend the off-host cross-compilation approach to all remaining s390x Bazel builds on v9.0, v8.3, and v8.0.

One confirmed example is rhel83-s390x-bazel-compile in the v9.0 and v8.3 Evergreen configurations: it runs compile_bazel_TG on rhel83-zseries-large. Native compilation also remains in unit-test, integration-test, and dbtest task paths after the release-build migration.

Scope

• Audit every s390x variant and Bazel build task on v9.0, v8.3, and v8.0, including non-release/Bazel-check variants, shared/dynamic builds, and compilation or linking embedded in test task groups.
• Move all remaining Bazel compilation and linking to suitable off-host cross-compilation workers, reusing the branch-appropriate cross toolchains and pinned target sysroots introduced by SERVER-136176.
• Where tasks currently combine building and running tests, separate off-host building from native s390x test execution and transfer the required artifacts.
• Preserve each branch's compiler/linker settings, target architecture and distribution metadata, test coverage, artifact publication, and task dependencies. Keep native runtime setup and test execution on s390x.

Acceptance Criteria

• No remaining s390x Bazel compilation or linking runs on native zSeries hosts on any of the three branches, including non-release variants and build stages embedded in test tasks.
• Evergreen patches validate the affected build variants and native unit tests, integration tests, and dbtests against the cross-built artifacts.
• Changes are completed for v9.0, v8.3, and v8.0. Master Affected is No.

Related Work

• Follow-up to SERVER-136176 and its backports BACKPORT-30058 (v9.0), BACKPORT-30092 (v8.3), and BACKPORT-30093 (v8.0).
• Epic: DEVPROD-43701 (Cross Compile Z Series and PPC platforms on dynamically allocated hosts).