[flang][runtime] Fix list-directed/NAMELIST complex input with "r*" repetition count

[klausler]

Summary

The little state machine in GetNextDataEdit() wasn't transitioning
properly from reading the imaginary part of the number back to the
real part for the next iteration of a repeated value.

flang/runtime/io-stmt.cpp

     if (remaining_ > 0) {
       repeatPosition_.emplace(io);
     }
-    return edit;
+    if (!imaginaryPart_) {
+      return edit;
+    }
   }
   // Skip separators, handle a "r*c" repeat count; see 13.10.2 in Fortran 2018
   if (imaginaryPart_) {