Change policy with legacy compiler backend

[JS] Remove incremental js jps test

[JS] Remove test of maven js archetype

[JS] Fix another one test

[JS] Fix tests for jps

[JS] Try to fix maven test data

[JS] Fix test data

[JS] Fix test data for ant

[JS] Fix jsExtraHelp test

[JS] Fix test run from not-Gradle build tools

[JS] Set flag without compiler error

[JS] Disable warnings and errors in legacy compiler called from Gradle

[JS] Proofread messages

[JS] Not proofread messages

KT-42326

compiler/testData/integration/ant/js/bothPrefixAndPostfix/build.xml

@@ -5,6 +5,8 @@
     <kotlin2js src="${test.data}/root1"
                output="${temp}/out.js"
                outputPrefix="${test.data}/prefix"
-               outputPostfix="${test.data}/postfix" />
+               outputPostfix="${test.data}/postfix">
+      <compilerarg value="-Xuse-deprecated-legacy-compiler"/>
+    </kotlin2js>
   </target>
 </project>