[Bug fortran/45424] [F08] Add IS_CONTIGUOUS intrinsic

[markeggleston at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45424
Bug 45424 depends on bug 53298, which changed state.

Bug 53298 Summary: ICE in gfc_conv_scalarized_array_ref for ARRAY + substring
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53298

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED