gdb: skip to GDB version string

This change allows to use ~/.gdbinit file with constructions like
`skip -gfi /usr/include/c++/*`.
Problem with current implementation is that when .gdbinit contains such
strings GDB output produced is following:
```
File(s) /usr/include/c++/* will be skipped when stepping.
GNU gdb (Ubuntu 8.2.91.20190405-0ubuntu3) 8.2.91.20190405-git
```
And current implementation expects version on the first output from GDB.

This change fixes it by adding skip functionality during GDB session
initialization.

BUG: 409702, 428688, 446786
FIXED-IN: 5.12.230800