[flang][runtime] Signal record read overrun when PAD='NO'

When PAD='NO' and ADVANCE='YES', we currently signal an input
error when a formatted read tries to go past the end of a record
only when a fixed RECL= is in effect.  Other compilers will signal
an error without RECL= too, and that seems like a precedent we
should follow.

Differential Revision: https://reviews.llvm.org/D124301