[SIL Printer] Add optional source location printing.

Added a -v(verbose) option to swift that will trigger verbose printing in SIL
Printer. SIL Printer will print the location info only in the verbose mode.

Here is the example of the format - only the line and colon are displayed for
brevity:

%24 = apply %13(%22) : $[cc(method), thin] ((), [byref] Bool) -> Builtin.Int1 // user: %26 line:46:10

(This will be used to test the validity of SILLocation info.)

Swift SVN r6991

include/swift/SIL/SILModule.h

@@ -176,8 +176,10 @@ public:
   void dump() const;
 
   /// Pretty-print the module to the designated stream.
-  void print(raw_ostream &OS) const;
-  
+  ///
+  /// \param Verbose Dump SIL location information in verbose mode.
+  void print(raw_ostream &OS, bool Verbose = false) const;
+
   /// Allocate memory using the module's internal allocator.
   void *allocate(unsigned Size, unsigned Align) const {
     if (TheASTContext.LangOpts.UseMalloc)