MC: Add MCSymbolData back to MCAssembler dump
MC: Add MCSymbolData back to MCAssembler dump

r237490 accidentally dropped MCSymbolData from the MCAssembler dump.
Add it back underneath the MCSymbol dump.  Remove the MCSymbol dump from
MCSymbolData, since this would cause an infinite co-recursion, and
besides, that back pointer is going away.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@237807 91177308-0d34-0410-b5e6-96231b3b80d8

dslab-epfl/asap,dslab-epfl/asap,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,dslab-epfl/asap,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap