utils: replace assert() by on_internal_error()

In issue #17035 we had a situation where a certain input timestamp
could result in the create_time() utility function getting called on
a timestamp that cannot be represented as timeuuid, and this resulted
in an *assertion failure*, and a crash.

I guess we used an assertion because we believed that callers try to
avoid calling this function on excessively large timestamps, but
evidentally, they didn't tried hard enough and we got a crash.
The code in UUID_gen.hh changed a lot over the years and has become
very convoluted and it is almost impossible to understand all the
code paths that could lead to this assertion failures. So it's better
to replace this assertion by a on_internal_error, which by default
is just an exception - and also logs the backtrace of the failure.
Issue #17035 would have been much less serious if we had an exception
instead of an assert.

Refs #17035
Refs #7871, Refs #13970 (removes an assert)

Signed-off-by: Nadav Har'El <nyh@scylladb.com>

utils/UUID_gen.hh

@@ -17,6 +17,7 @@
 #include <limits>
 
 #include "UUID.hh"
+#include "on_internal_error.hh"
 
 namespace utils {
 
@@ -383,7 +384,11 @@ public:
         auto dmc = duration_cast<decimicroseconds>(d);
         uint64_t msb = dmc.count();
         // timeuuid time must fit in 60 bits
-        assert(!(0xf000000000000000UL & msb));
+        if ((0xf000000000000000UL & msb)) {
+            // We hope callers would try to avoid this case, but they don't
+            // always do, so assert() would be bad here - and caused #17035.
+            utils::on_internal_error("timeuuid time must fit in 60 bits");
+        }
         return ((0x00000000ffffffffL & msb) << 32 |
                (0x0000ffff00000000UL & msb) >> 16 |
                (0x0fff000000000000UL & msb) >> 48 |