Add error handling in lock initialization in the Xtensa port #67

All 540 tests pass in 4m 40s

540 tests ±0 540 ✔️ ±0 4m 40s ⏱️ ±0s
    5 suites ±0     0 💤 ±0
    5 files ±0     0 ❌ ±0

Results for commit e92e750. ± Comparison against earlier commit 8fbd23d.