Rename module in real16 test

When the utility module had the same name in both tests, we
get errors because of multiple build rules for the module.
Renamed to resolve the conflict.

Author: ashermancinelli

Fortran/UnitTests/fp_conversions/fp_convert_r16.f90

@@ -1,4 +1,4 @@
-module fp_convert_m
+module fp_convert_r16_m
   implicit none
   type answer
     integer(kind=1)   :: i8
@@ -49,11 +49,11 @@ subroutine testcase(value)
     result = do_conversion(value)
     call print_answer(result)
   end subroutine
-end module fp_convert_m
+end module fp_convert_r16_m
 
-program fp_convert
+program fp_convert_r16
   use ieee_arithmetic, only: ieee_value, ieee_quiet_nan, ieee_positive_inf, ieee_negative_inf
-  use fp_convert_m
+  use fp_convert_r16_m
   implicit none
 
   real(kind=16) :: r128, nan, inf, ninf
@@ -83,4 +83,4 @@ program fp_convert
   print *, "nan"
   call testcase(nan)
 
-end program fp_convert
+end program fp_convert_r16