[SymbolContext] Rewrite operator== to be more concise.
[SymbolContext] Rewrite operator== to be more concise.

And probably, less error prone. NFCI.

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@350146 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb