Frontend: add an option -bad-file-descriptor-retry-count

This option allows the compiler to retry opening an input file if the previous
opening returns an error of bad file descriptor. Swift-driver will set this
argument in certain circumstances to walk-around such error.

rdar://73157185

include/swift/Frontend/FrontendOptions.h

@@ -86,6 +86,9 @@ public:
   /// The module for which we should verify all of the generic signatures.
   std::string VerifyGenericSignaturesInModule;
 
+  /// Number of retry opening an input file if the previous opening returns
+  /// bad file descriptor error.
+  unsigned BadFileDescriptorRetryCount = 0;
   enum class ActionType {
     NoneAction,        ///< No specific action
     Parse,             ///< Parse only