Problem

In SERVER-121715 we reduced the resmoke_jobs_factor for TSAN variants to avoid OOM issues, but the fix in VARIANT_TASK_FACTOR_OVERRIDES was too restrictive — it only matched the exact variant names enterprise-rhel8-debug-tsan and enterprise-rhel8-debug-tsan-all-feature-flags.

The full list of TSAN variants includes many more that are not covered:

• enterprise-rhel8-debug-tsan-all-non-rollback-feature-flags
• enterprise-rhel8-debug-tsan-compile
• enterprise-rhel8-debug-tsan-roll-back-incremental-feature-flags
• enterprise-rhel8-streams-tsan
• linux-arm64-tsan-essential-required

As a result, these variants still run out of memory on memory-intensive sharding suites.

Proposed Solution

1. Update get_task_factor to iterate over all override keys and use re.fullmatch for variant matching, so regex patterns can be used as dictionary keys in VARIANT_TASK_FACTOR_OVERRIDES.
2. Add a new r"enterprise-rhel8-debug-tsan.*" regex entry in VARIANT_TASK_FACTOR_OVERRIDES and move the shared task factor overrides (sharding_kill_stepdown_terminate_jscore_passthrough, sharding_stepdown_fcv_upgrade_downgrade_jscore_passthrough, sharding_jscore_passthrough_priority_ports) into it so they apply to all matching TSAN variants.