swift

8293bdc9 - SerilizeLoc: refactor table structures per Jordan's comments

SerilizeLoc: refactor table structures per Jordan's comments After this change, we only use one single hash table for USR to USR id mapping. The basic source locations are an array of fixed length records that could be retrieved by using the USR id since each USR id is guaranteed to be associated with one basic location entry. The source file paths are refactored to a blob of 0-terminated strings. Decl locations use offset in this blob to refer to the source file path where the decl was defined.