Remove empty TLD parameter when fanning out without TLDs

TldFanoutAction fans out a given endpoint to all TLDs (either TEST, REAL, or
both).

However, it is also used to delegate a single endpoint request that we want set
in a specific queue (so we can control retries). We do that by setting the TLD
list to "runInEmpty" rather than "forEachRealTld" or "forEachTestTld".

Currently, using "runInEmpty" would still specify a TLD - but that TLD would be
the empty string. This is a bug: it sets the TLD parameter to a bad value. It
worked only because none of the endpoints called with "runInEmpty" were using
the TLD parameter.

However, this will (and does) break if either (a) the endpoint accepts an
optional TLD parameter (like deleteProberData does), or (b) the given endpoint
already has a TLD parameter in it (we want to run the endpoint with a single
TLD, but still use the "fanout" to set the right queue).

This CL fixes several things:

- if runInEmpty is given, no TLD parameter is added
- 'runInEmpty' is now mutually exclusive with 'forEach*Tld' and 'excludes'
- we do some sanity checks and added logging
- removed the buggy and unused "':tld' in path is replaced by TLD"
- in the cron.xml, removed documentation for :tld and the broken :registrar

Note that none of the endpoints that were used with runInEmpty fanout had the TLD parameter prior to deleteProberData

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=189954585

java/google/registry/env/alpha/default/WEB-INF/cron.xml

@@ -5,9 +5,7 @@
     /cron/fanout params:
         queue=<QUEUE_NAME>
         endpoint=<ENDPOINT_NAME>    // URL Path of servlet, which may contain placeholders:
-                                    //   :tld       - Replaced with the TLD, e.g. foo, soy
-                                    //   :registrar - Replaced with registrar clientId
-        runInEmpty                  // Run in the empty namespace
+        runInEmpty                  // Run once, with no tld parameter
         forEachRealTld              // Run for tlds with getTldType() == TldType.REAL
         forEachTestTld              // Run for tlds with getTldType() == TldType.TEST
         exclude=TLD1[&exclude=TLD2] // exclude something otherwise included

java/google/registry/env/production/default/WEB-INF/cron.xml

@@ -5,9 +5,7 @@
     /cron/fanout params:
         queue=<QUEUE_NAME>
         endpoint=<ENDPOINT_NAME>    // URL Path of servlet, which may contain placeholders:
-                                    //   :tld       - Replaced with the TLD, e.g. foo, soy
-                                    //   :registrar - Replaced with registrar clientId
-        runInEmpty                  // Run in the empty namespace
+        runInEmpty                  // Run once, with no tld parameter
         forEachRealTld              // Run for tlds with getTldType() == TldType.REAL
         forEachTestTld              // Run for tlds with getTldType() == TldType.TEST
         exclude=TLD1[&exclude=TLD2] // exclude something otherwise included

java/google/registry/env/sandbox/default/WEB-INF/cron.xml

@@ -5,9 +5,7 @@
     /cron/fanout params:
         queue=<QUEUE_NAME>
         endpoint=<ENDPOINT_NAME>    // URL Path of servlet, which may contain placeholders:
-                                    //   :tld       - Replaced with the TLD, e.g. foo, soy
-                                    //   :registrar - Replaced with registrar clientId
-        runInEmpty                  // Run in the empty namespace
+        runInEmpty                  // Run once, with no tld parameter
         forEachRealTld              // Run for tlds with getTldType() == TldType.REAL
         forEachTestTld              // Run for tlds with getTldType() == TldType.TEST
         exclude=TLD1[&exclude=TLD2] // exclude something otherwise included