Use exec_and_log in next.py

Some code in next.py avoids exec_and_log due to its exception
behavior.  Now that exec_and_log always forwards exceptions, this is
easily fixed.

gdb/python/lib/gdb/dap/next.py

diff --git a/gdb/python/lib/gdb/dap/next.py b/gdb/python/lib/gdb/dap/next.py
index a0fa18e..993e9d2 100644
--- a/gdb/python/lib/gdb/dap/next.py
+++ b/gdb/python/lib/gdb/dap/next.py
@@ -17,7 +17,7 @@
 
 from .events import exec_and_expect_stop
 from .server import capability, request
-from .startup import in_gdb_thread
+from .startup import DAPException, exec_and_log, in_gdb_thread
 from .state import set_thread
 
 
@@ -36,11 +36,9 @@
         result = False
         arg = "off"
     try:
-        # This can fail, depending on the target, so catch the error
-        # and report to our caller.  We can't use exec_and_log because
-        # that does not propagate exceptions.
-        gdb.execute("set scheduler-locking " + arg, from_tty=True, to_string=True)
-    except gdb.error:
+        # This can fail, depending on the target, so catch any error.
+        exec_and_log("set scheduler-locking " + arg)
+    except DAPException:
         result = False
     # Other DAP code may select a frame, and the "finish" command uses
     # the selected frame.