Change raw_fd_ostream to take flags as an optional bitmask 
instead of as two bools.  Use this to add a F_Append flag
which has the obvious behavior.

Other unrelated changes conflated into this patch:

1. REmove EH stuff from llvm-dis and llvm-as, the try blocks
   are dead.
2. Simplify the filename inference code in llvm-as/llvm-dis,
   because raw_fd_ostream does the right thing with '-'.
3. Switch machine verifier to use raw_ostream instead of ostream
   (Which is the thing that needed append in the first place).




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79807 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/TableGen.cpp b/utils/TableGen/TableGen.cpp
index 315bb65..3e284f9 100644
--- a/utils/TableGen/TableGen.cpp
+++ b/utils/TableGen/TableGen.cpp
@@ -171,8 +171,8 @@
   raw_ostream *Out = &outs();
   if (OutputFilename != "-") {
     std::string Error;
-    Out = new raw_fd_ostream(OutputFilename.c_str(), /*Binary=*/false,
-                             /*Force=*/true, Error);
+    Out = new raw_fd_ostream(OutputFilename.c_str(), Error,
+                             raw_fd_ostream::F_Force);
 
     if (!Error.empty()) {
       errs() << argv[0] << ": error opening " << OutputFilename