Removed '-r2r' shorthand flag due to it conflicting with -r because of a bug in the Command Line API (#56934)

Author: ivdiazsa

src/coreclr/tools/r2rtest/CommandLineOptions.cs

@@ -279,7 +279,7 @@ Option ExecutionTimeoutMinutes() =>
                 new Option<int>(new[] { "--execution-timeout-minutes", "-et" }, "Execution timeout (minutes)");
 
             Option R2RDumpPath() =>
-                new Option<FileInfo>(new[] { "--r2r-dump-path", "-r2r" }, "Path to R2RDump.exe/dll").ExistingOnly();
+                new Option<FileInfo>(new[] { "--r2r-dump-path" }, "Path to R2RDump.exe/dll").ExistingOnly();
 
             Option MeasurePerf() =>
                 new Option<bool>(new[] { "--measure-perf" }, "Print out compilation time");