Intent of mapper.go ×2

All 3 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 3 tests
- server/ 3 tests
  - common/ 3 tests
    
    searchattribute/ 3 tests
    
    go.temporal.io/server/common/searchattribute/TestMapperProviderDoesNotTreatPreallocatedFieldsAsLegacyCustomAttributes Inherited mapper.go ×1
    
    go.temporal.io/server/common/searchattribute/TestMapperProviderUsesConfiguredVisibilityIndexForBackCompatFallback Inherited namespace.go ×1
    
    go.temporal.io/server/common/searchattribute/Test_BackCompMapperFallsBackToClusterMetadataFields Inherited Test_BackCompMapperFallsBackToClusterMetadataFields