Test transparent huge pages on Linux (#278)

* Adding ability to use THP on Linux

* Use the actual page size4 used for mmap also in munmap

* Add -thp to llama-bench

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Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>

include/llama.h

@@ -345,6 +345,7 @@ extern "C" {
         bool use_mlock;     // force system to keep model in RAM
         bool check_tensors; // validate model tensor data
         bool repack_tensors;// repack if available
+        bool use_thp;       // uase transparent huge pages (linux only)
     };
 
     // NOTE: changing the default values of parameters marked as [EXPERIMENTAL] may cause crashes or incorrect results in certain configurations