IC should be enabled explicitly by build systems

The change only affects JPS on TeamCity (in Intellij IC system property
is always set explicitly; the same holds for Gradle, Maven).
Previous changes have effectively enabled the new IC (which is now default)
for TC JPS builds, which is undesirable as more RAM is used.

idea/testData/modules.xml/filtered.xml

@@ -5,7 +5,10 @@
         <sources path="s2"/>
         <!-- Java source roots -->
         <!-- Classpath -->
-        <classpath path="cp1"/>
+        <!-- Output directory, commented out -->
+        <!--
+            <classpath path="cp1"/>
+        -->
         <classpath path="cp2"/>
     </module>
 </modules>

idea/testData/modules.xml/multiple.xml

@@ -5,7 +5,10 @@
         <sources path="s2"/>
         <!-- Java source roots -->
         <!-- Classpath -->
-        <classpath path="cp1"/>
+        <!-- Output directory, commented out -->
+        <!--
+            <classpath path="cp1"/>
+        -->
         <classpath path="cp2"/>
     </module>
     <!-- Module script for tests -->
@@ -14,7 +17,10 @@
         <sources path="s22"/>
         <!-- Java source roots -->
         <!-- Classpath -->
-        <classpath path="cp12"/>
+        <!-- Output directory, commented out -->
+        <!--
+            <classpath path="cp12"/>
+        -->
         <classpath path="cp22"/>
     </module>
 </modules>