[obj2yamp] - Simplify and cleanup the code in ELFDumper<ELFT>::dumpGroup a bit. NFC.
[obj2yamp] - Simplify and cleanup the code in ELFDumper<ELFT>::dumpGroup a bit. NFC.

This makes the variables naming to match LLVM style,
simplifies the code used to extract the group members,
simplifies the loop and reorders the code around a bit.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@359101 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm