[JS DCE] Add an ability to define overwriting strategy when copying dependencies in dev-mode

* CLI option "-Xdev-mode-overwriting-strategy"
* System Property "kotlin.js.dce.devmode.overwriting.strategy"

Possible values: "older", "all".

#KT-36349 Fixed

compiler/testData/cli/js-dce/dceExtraHelp.out

@@ -0,0 +1,8 @@
+Usage: kotlin-dce-js <options> <source files>
+where advanced options include:
+  -Xdev-mode-overwriting-strategy={older|all}
+                             Overwriting strategy during copy dependencies in development mode
+  -Xprint-reachability-info  Print declarations marked as reachable
+
+Advanced options are non-standard and may be changed or removed without any notice.
+OK