Bug#59307 Valgrind: uninitialized value in rw_lock_set_writer_id_and_recursion_flag()

rw_lock_create_func(): Initialize lock->writer_thread, so that Valgrind
will not complain even when Valgrind instrumentation is not enabled.
Flag lock->writer_thread uninitialized, so that Valgrind can complain
when it is used uninitialized.

rw_lock_set_writer_id_and_recursion_flag(): Revert the bogus Valgrind
instrumentation that was pushed in the first attempt to fix this bug.

mysql-test/suite/innodb_plugin/t/innodb_bug59307.test

@@ -0,0 +1,32 @@
+-- source include/have_innodb_plugin.inc
+# Bug #59307 uninitialized value in rw_lock_set_writer_id_and_recursion_flag()
+# when Valgrind instrumentation (UNIV_DEBUG_VALGRIND) is not enabled
+
+CREATE TABLE t1 (
+  t1_int INT,
+  t1_time TIME
+) ENGINE=innodb;
+
+CREATE TABLE t2 (
+  t2_int int PRIMARY KEY,
+  t2_int2 INT
+) ENGINE=INNODB;
+
+INSERT INTO t2 VALUES ();
+INSERT INTO t1 VALUES ();
+
+SELECT *
+FROM t1 AS t1a
+WHERE NOT EXISTS
+  (SELECT *
+   FROM t1 AS t1b
+   WHERE t1b.t1_int NOT IN
+     (SELECT t2.t2_int
+      FROM t2
+      WHERE t1b.t1_time LIKE t1b.t1_int
+      OR t1b.t1_time <> t2.t2_int2
+      AND 6=7
+ )
+)
+;
+DROP TABLE t1,t2;