[clang] [Driver] Add .hasAnySanitizer() to SanitizerArgs

[mgorny]

Summary

Add a simple method to query whether any sanitizer was enabled,
via SanitizerArgs. This will be used in the NetBSD driver to pass
additional definitions that are required by all sanitizers.

cfe/trunk/include/clang/Driver/SanitizerArgs.h

bool needsEsanRt() const {
     return Sanitizers.hasOneOf(SanitizerKind::Efficiency);
   }
   bool needsScudoRt() const { return Sanitizers.has(SanitizerKind::Scudo); }
 
   bool requiresPIE() const;
   bool needsUnwindTables() const;
   bool linkCXXRuntimes() const { return LinkCXXRuntimes; }
   bool hasCrossDsoCfi() const { return CfiCrossDso; }
+  bool hasAnySanitizer() const { return !Sanitizers.empty(); }
   void addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
                llvm::opt::ArgStringList &CmdArgs, types::ID InputType) const;
 };
 
 }  // namespace driver
 }  // namespace clang
 
 #endif