MDEV-38838 Memory loss in CONNECT from handler::ha_rnd_init

This was a leak in unixODBC 2.3.14 where a cache was allocated
but not returned. The LD_PRELOAD is so the resolution will be
aware of the resolution for save_ini_cache that caused the leak.

Alterates considered:
1. __clear_ini_cache in libodbcinst (2.3.12+) is an interface,
for which there is no header define. A CMake would need to
do full compile and link to check its existance. Workable,
just wanted a simplier solution. It looked like it shoud be a
better interface in unixODBC.

2. could skip asan tests on CONNECT/ODBC, but this is skipping
coverage we want.

Author: grooverdan

mysql-test/lsan.supp

@@ -15,3 +15,6 @@ leak:gnutls_x509_trust_list_init
 leak:gnutls_subject_alt_names_init
 leak:__gmp_default_allocate
 leak:__gmp_default_reallocate
+
+# unixODBC leak
+leak:save_ini_cache

storage/connect/mysql-test/connect/suite.pm

@@ -10,7 +10,51 @@ return "No CONNECT engine" unless $ENV{HA_CONNECT_SO} or
 return "Not run for embedded server" if $::opt_embedded_server and
                                         $ENV{HA_CONNECT_SO};
 
-sub is_default { 1 }                                  
+sub is_default { 1 }
+
+# To allow the lsan suppression on unixodbc to work
+# the llvm-symbolizer needs to be are of the address
+# resolution even after the HA_CONNECT_SO has been dlclosed.
+
+# Check OS and file existence
+if ($^O =~ /linux|darwin|unix/i && -x "/usr/bin/readelf")
+{
+  my $asan_symbols = 0;
+  my $file = $::plugindir . '/' .  $ENV{HA_CONNECT_SO};
+
+  # Open readelf -s output and scan for __asan symbols
+  open(my $sh, '-|', "readelf -s '$file'")
+      or die "Failed to run readelf: $!\n";
+  while (<$sh>) { $asan_symbols = 1 if /__asan/; }
+  close($sh);
+
+  if ($asan_symbols && -x "/usr/bin/ldd")
+  {
+    # To allow the lsan suppression on unixodbc to work
+    # the llvm-symbolizer needs to be aware of the address
+    # resolution even after the HA_CONNECT_SO has been dlclosed.
+
+    my $lib_path;
+    open(my $ldd, '-|', "ldd $file") or die "Failed to run ldd: $!";
+
+    while (<$ldd>)
+    {
+        chomp;
+        # Example ldd line: libodbc.so.2 => /usr/lib/x86_64-linux-gnu/libodbc.so.2 (0x00007f...)
+        if (/libodbc\.so(?:\.\d+)*\s+=>\s+(\S+)/)
+	{
+            $lib_path = $1;
+            last;  # stop after the first match
+        }
+    }
+    close $ldd;
+
+    if ($lib_path)
+    {
+      $ENV{LD_PRELOAD} = $ENV{LD_PRELOAD} ? "$ENV{LD_PRELOAD}:$lib_path" : $lib_path;
+    }
+  }
+}
 
 bless { };