[SEH] Remove the old __C_specific_handler code now that WinEHPrepare works

This removes the -sehprepare flag and makes __C_specific_handler
functions always to use WinEHPrepare.

This was tested by building all of chromium_builder_tests and running a
few tests that use SEH, but if something breaks, we can revert this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235557 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineModuleInfo.h

@@ -77,7 +77,6 @@ struct LandingPadInfo {
   MachineBasicBlock *LandingPadBlock;      // Landing pad block.
   SmallVector<MCSymbol *, 1> BeginLabels;  // Labels prior to invoke.
   SmallVector<MCSymbol *, 1> EndLabels;    // Labels after invoke.
-  SmallVector<MCSymbol *, 1> ClauseLabels; // Labels for each clause.
   SmallVector<SEHHandler, 1> SEHHandlers;  // SEH handlers active at this lpad.
   MCSymbol *LandingPadLabel;               // Label at beginning of landing pad.
   const Function *Personality;             // Personality function.
@@ -361,11 +360,6 @@ public:
   ///
   void addCleanup(MachineBasicBlock *LandingPad);
 
-  /// Add a clause for a landing pad. Returns a new label for the clause. This
-  /// is used by EH schemes that have more than one landing pad. In this case,
-  /// each clause gets its own basic block.
-  MCSymbol *addClauseForLandingPad(MachineBasicBlock *LandingPad);
-
   void addSEHCatchHandler(MachineBasicBlock *LandingPad, const Function *Filter,
                           const BlockAddress *RecoverLabel);