[gdb/testsuite] Make gdb.reverse/time-reverse.exp more robust

[gdb/testsuite] Make gdb.reverse/time-reverse.exp more robust

I noticed that test-case gdb.reverse/time-reverse.exp contains:
...
    if [supports_process_record] {
        # Activate process record/replay
        gdb_test_no_output "record" "turn on process record"
...

So I tried out forcing supports_process_record to 0, and got:
...
FAIL: gdb.reverse/time-reverse.exp: mode=syscall: info record
FAIL: gdb.reverse/time-reverse.exp: mode=syscall: reverse to marker1
FAIL: gdb.reverse/time-reverse.exp: mode=syscall: check time record
FAIL: gdb.reverse/time-reverse.exp: mode=c: info record
FAIL: gdb.reverse/time-reverse.exp: mode=c: reverse to marker1
FAIL: gdb.reverse/time-reverse.exp: mode=c: check time record
...

Fix this by requiring supports_process_record alongside supports_reverse.

I also noticed when running make-check-all.sh that there were a lot of failures
with target board dwarf5-fission-debug-types.

Fix this by not ignoring the result of "runto marker1".

Then I noticed that $srcfile is used as a regexp.  Fix this by applying
string_to_regexp.

Tested on x86_64-linux.

Approved-By: Guinevere Larsen <guinevere@redhat.com>