Rename set-solib-absolute-prefix.exp to x86-set-solib-absolute-prefix.exp

and move it from gdb.base to gdb.arch as it's a target specific test.

Reviewed-by: Maciej W. Rozycki <macro@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>

diff --git a/gdb/testsuite/gdb.base/set-solib-absolute-prefix.c b/gdb/testsuite/gdb.arch/x86-set-solib-absolute-prefix.c
similarity index 100%
rename from gdb/testsuite/gdb.base/set-solib-absolute-prefix.c
rename to gdb/testsuite/gdb.arch/x86-set-solib-absolute-prefix.c

diff --git a/gdb/testsuite/gdb.base/set-solib-absolute-prefix.exp b/gdb/testsuite/gdb.arch/x86-set-solib-absolute-prefix.exp
similarity index 100%
rename from gdb/testsuite/gdb.base/set-solib-absolute-prefix.exp
rename to gdb/testsuite/gdb.arch/x86-set-solib-absolute-prefix.exp