Extract vm_locked_by_ractor_p

This introduces a new method to encapsulate checking whether the current
Ractor owns the vm->ractor.sync lock. This allows us to disable TSan on
it since that operation should be safe, and still get validation of
other uses.

misc/tsan_suppressions.txt

@@ -30,13 +30,6 @@ race:check_reserved_signal_
 
 race_top:rb_check_deadlock
 
-# lock_owner
-race_top:thread_sched_setup_running_threads
-race_top:vm_lock_enter
-race_top:rb_ec_vm_lock_rec
-race_top:vm_lock_enter
-race_top:vm_locked
-
 # vm->ractor.sched.grq_cnt++
 race_top:ractor_sched_enq
 race_top:ractor_sched_deq

vm_core.h

@@ -2065,12 +2065,21 @@ void rb_ec_vm_lock_rec_release(const rb_execution_context_t *ec,
                                unsigned int recorded_lock_rec,
                                unsigned int current_lock_rec);
 
+/* This technically is a data race, as it's checked without the lock, however we
+ * check against a value only our own thread will write. */
+NO_SANITIZE("thread", static inline bool
+vm_locked_by_ractor_p(rb_vm_t *vm, rb_ractor_t *cr))
+{
+    VM_ASSERT(cr == GET_RACTOR());
+    return vm->ractor.sync.lock_owner == cr;
+}
+
 static inline unsigned int
 rb_ec_vm_lock_rec(const rb_execution_context_t *ec)
 {
     rb_vm_t *vm = rb_ec_vm_ptr(ec);
 
-    if (vm->ractor.sync.lock_owner != rb_ec_ractor_ptr(ec)) {
+    if (!vm_locked_by_ractor_p(vm, rb_ec_ractor_ptr(ec))) {
         return 0;
     }
     else {

vm_sync.c

@@ -12,7 +12,7 @@ void rb_ractor_sched_barrier_end(rb_vm_t *vm, rb_ractor_t *cr);
 static bool
 vm_locked(rb_vm_t *vm)
 {
-    return vm->ractor.sync.lock_owner == GET_RACTOR();
+    return vm_locked_by_ractor_p(vm, GET_RACTOR());
 }
 
 #if RUBY_DEBUG > 0