Intent of id_mutex.go ×2

All 2 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 2 tests
- server/ 2 tests
  - common/ 2 tests
    
    locks/ 2 tests
    
    TestIDMutexSuite/ 2 tests
    
    go.temporal.io/server/common/locks/TestIDMutexSuite/TestConcurrentAccess Introduced here
    
    go.temporal.io/server/common/locks/TestIDMutexSuite/TestLockOnSameID Introduced here