Revert "Revert "[llvm-objdump] Allow short options without arguments to be grouped""

  - Tests that use multiple short switches now test them grouped and ungrouped.

  - Ensure the output of ungrouped and grouped variants is identical

Differential Revision: https://reviews.llvm.org/D57904

llvm-svn: 354375
diff --git a/llvm/tools/llvm-objdump/MachODump.cpp b/llvm/tools/llvm-objdump/MachODump.cpp
index 549a203..72a8a01 100644
--- a/llvm/tools/llvm-objdump/MachODump.cpp
+++ b/llvm/tools/llvm-objdump/MachODump.cpp
@@ -59,7 +59,7 @@
 using namespace object;
 
 static cl::opt<bool>
-    UseDbg("g",
+    UseDbg("g", cl::Grouping,
            cl::desc("Print line information from debug info if available"));
 
 static cl::opt<std::string> DSYMFile("dsym",