tilegx: Fix infinite loop in gen-mul-tables generator
Since around GCC 10, the condition `j < (INTMAX_MAX / 10)' will get
optimized into `j !=
922337203685477580', which will result in an
infinite loop for certain inputs of `j'.
Copy the condition already used by the -DTILEPRO generator code, which
doesn't fall into this trap.
gcc/ChangeLog:
* config/tilepro/gen-mul-tables.cc (tilegx_emit): Adjust loop
condition to avoid overflow.
(cherry picked from commit
c0ad48527c314a1e9354b7c26718b56ed4abc92c)