gdb/mi: add no-history stop reason

When executing in reverse and runs out of recorded history, GDB prints
a warning to the user, but does not add a reason in the stopped record,
for example:

*stopped,frame={addr="0x000000000040113e",func="main",args=[],file="/home/blarsen/Documents/fsf_build/gdb/testsuite/../../../binutils-gdb/gdb/testsuite/gdb.reverse/solib-reverse.c",fullname="/home/blarsen/Documents/binutils-gdb/gdb/testsuite/gdb.reverse/solib-reverse.c",line="27",arch="i386:x86-64"},thread-id="1",stopped-threads="all",core="1"

This problem was reported as record/29260.

This commit adds the reason no-history to the record, making it easier
for interfaces using the mi interpreter to report the result.  It also
changes the test gdb.mi/mi-reverse.exp to test that the reason shows up
correctly.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29260

gdb/testsuite/gdb.mi/mi-reverse.exp

@@ -159,7 +159,7 @@ proc test_controlled_execution_reverse {} {
         "reverse-continue at callee3"
 
     mi_execute_to "exec-continue --reverse" \
-        "" "main" "" \
+        "no-history" "main" "" \
         "basics.c" $line_main_body "" \
         "reverse-continue at main"
 }