[flang][MIF] Fix undef reference to a coarray_handle in mif.dealloc_coarray #193157 (#213890) This PR fixes the behavior reported in issue #193157. The coarray_handle was only defined if a call to mif.alloc_coarray was present. If a call to mif.dealloc_coarray was encountered without a prior call to mif.alloc_coarray, then the coarray_handle was missing, and therefore llvm.address_of pointed to a non-existent address, which is not allowed. We now define a coarray_handle that has not been allocated by PRIF for each coarray variables. GitOrigin-RevId: a9426776e78a89dec776c34efdb7725de591d878
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