Fix mixed threadlocal and supplied random use (elastic#52459)

Closes elastic#52450. `setRandomIndexSettings(...)` in `ESIntegTestCase` was
using both a thread-local and a supplied source of randomness. Fix this
method to only use the supplied source.

Author: pugnascotia

test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java

@@ -448,10 +448,10 @@ protected Settings.Builder setRandomIndexSettings(Random random, Settings.Builde
         }
 
         if (random.nextBoolean()) {
-            builder.put(IndexSettings.INDEX_CHECK_ON_STARTUP.getKey(), randomFrom("false", "checksum", "true"));
+            builder.put(IndexSettings.INDEX_CHECK_ON_STARTUP.getKey(), randomFrom(random, "false", "checksum", "true"));
         }
 
-        if (randomBoolean()) {
+        if (random.nextBoolean()) {
             // keep this low so we don't stall tests
             builder.put(UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(),
                     RandomNumbers.randomIntBetween(random, 1, 15) + "ms");