build scripts cleanup: removed obsolete method

dataStorageRoot is now cleaned in JpsGantProjectBuilder#cleanOutput.

build/scripts/common_tests.gant

@@ -36,7 +36,6 @@ target(compile: "Compile project") {
   }
 
   if (!isDefined("avoid.project.rebuild")) {
-    clearBuildCaches()
     projectBuilder.cleanOutput()
     projectBuilder.buildAll()
   }

build/scripts/utils.gant

@@ -204,15 +204,6 @@ binding.setVariable("prepareOutputFolder", {
   }
 })
 
-binding.setVariable("clearBuildCaches", {
-  //todo[nik] this is temporary solution until we update bootstrap jps-builders jars to the new version where cleaning is performed in JpsGantProjectBuilder#cleanOutput
-  if (projectBuilder.buildIncrementally && !Boolean.parseBoolean(p("jps.build.clear.incremental.caches", "false"))) return 
-  def storageRoot = projectBuilder.dataStorageRoot
-  if (storageRoot != null) {
-    FileUtil.delete(storageRoot)
-  }
-})
-
 binding.setVariable("findModule", {String name ->
   project.modules.find { it.name == name }
 })
@@ -350,7 +341,6 @@ binding.setVariable("buildModulesAndCollectUsedJars", { List modules, List appro
   def modulesToBuild = []
   def modulesNames = modules.contains(javaRT) ? modules : [*modules, javaRT]
   def usedJars = collectUsedJars(modulesNames, approvedJars, forbiddenJars, modulesToBuild)
-  clearBuildCaches()
   projectBuilder.cleanOutput()
   projectBuilder.buildModules(modulesToBuild)