psxtests: Remove bogus file

This file is unused and makes trouble on Windows.

Updates #3638.

testsuites/psxtests/psxhdrs/math/expm1.

@@ -1,38 +0,0 @@
-/**
- *  @file
- *  @brief exp() API Conformance Test
- */
-
- /*
-  *  COPYRIGHT (c) 2018.
-  *  Shashvat Jain
-  *
-  *  Permission to use, copy, modify, and/or distribute this software
-  *  for any purpose with or without fee is hereby granted.
-  *
-  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
-  *  WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
-  *  WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
-  *  BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
-  *  OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
-  *  WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
-  *  ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-  */
-
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <math.h>
-
-int test( void );
-
-int test( void )
-{
-  double x = 0 ;
-  double result ;
-
-  result = expm1(x) ;
-
-  return (result);
-}