Fix issues with multiple inferiors

Fix issues with multiple inferiors

Issue #1:
Thread 3 "bit_extract_kernel" hit Breakpoint 1, bit_extract_kernel ()
(gdb) add-inferior
[New inferior 2]
Added inferior 2 on connection 1 (native)
(gdb) info threads
amd_dbgapi_wave_list failed (rc=-14)

An inferior may not have yet been attached when update_thread_list is
called. The inferior should be skipped if its process_id is null.

Issue #2:
Thread 3 "bit_extract_kernel" hit Breakpoint 1, bit_extract_kernel ()
(gdb) add-inferior -exec /bin/ls
[New inferior 2]
Added inferior 2 on connection 1 (native)
Reading symbols from /bin/ls...
(No debugging symbols found in /bin/ls)
(gdb) inferior 2
[Switching to inferior 2 [<null>] (/bin/ls)]
(gdb) run
Starting program: /bin/ls
Warning:
Cannot insert breakpoint -8.
Cannot access memory at address 0x7fffedaa265b

Internal ROCgdbapi breakpoints should not be re-evaluated for new
inferiors. They are inserted for a specific process_id, and removed
when the process is detached.

gdb/ChangeLog:
        * gdb/rocm-tdep.c: Skip inferiors without process_ids. Override
        breakpoint_ops::re_set for rocm internal breakpoints to
        disable re-evaluation.

Change-Id: Icb0be93b74aae1cf80c7f1657cf6d01e16eb8efb