These new test cases are to verify that tracepoint changed after
`tstart' still work properly.  There are two FAILs in change-loc.exp on
x86_64-linux, but they are not related to this patch set.  They are
caused by an existing problem that jmp insn is incorrectly generated in
jump pad if offset exceeds the limit of integer (32-bit).  It could
happen on x86_64 system.

I opened PR 13392, and KFAIL'ed them.

  KFAIL: gdb.trace/change-loc.exp: 1 trace: tfind frame 0 (PRMS: gdb/13392)
  KFAIL: gdb.trace/change-loc.exp: 1 ftrace: tfind frame 0 (PRMS: gdb/13392)

-- 
Yao (齐尧)