variable_watch: Remove leftover debugging code (#14187)

When a watch does not specify a command to call then variable_watch
prints out a message to stderr.  Remove code after that which collects
all variable values to construct a message that is never printed.
Otherwise such code causes a READ_ACCESS watch to trigger on all
variables in the currents scope.

Reported-by: Yichao Yu <[email protected]>

Source/cmVariableWatchCommand.cxx

@@ -122,19 +122,6 @@ void cmVariableWatchCommand::VariableAccessed(const std::string& variable,
     msg << "  The value of the variable: \"" << newValue << "\"" << std::endl;
     msg << "  The list file stack: " << stack.c_str();
     cmSystemTools::Message(msg.str().c_str());
-    std::vector<std::string> vars = makefile->GetDefinitions();
-    cmOStringStream msg2;
-    size_t cc;
-    for ( cc = 0; cc < vars.size(); cc ++ )
-      {
-      if ( vars[cc] == variable )
-        {
-        continue;
-        }
-      msg2 << vars[cc] << " = \""
-        << makefile->GetDefinition(vars[cc].c_str()) << "\"" << std::endl;
-      }
-    //cmSystemTools::Message(msg2.str().c_str());
     }
   this->InCallback = false;
 }

Tests/RunCMake/variable_watch/NoWatcher-stderr.txt

@@ -0,0 +1,4 @@
+my_func
+\* Variable "b" was accessed using MODIFIED_ACCESS in: .*/Tests/RunCMake/variable_watch/NoWatcher.cmake
+  The value of the variable: ""
+  The list file stack: .*/Tests/RunCMake/variable_watch/CMakeLists.txt;.*/Tests/RunCMake/variable_watch/NoWatcher.cmake$

Tests/RunCMake/variable_watch/NoWatcher.cmake

@@ -0,0 +1,8 @@
+function(my_func)
+  message("my_func")
+endfunction()
+variable_watch(a my_func)
+set(a "")
+
+variable_watch(b)
+set(b "")

Tests/RunCMake/variable_watch/RunCMakeTest.cmake

@@ -1,3 +1,4 @@
 include(RunCMake)
 
 run_cmake(ModifiedAccess)
+run_cmake(NoWatcher)