feat(Escaped Identifiers): add ability to use any symbol wrapped in back ticks.

js/js.translator/testData/box/escapedIdentifiers/externalEscapedCommonJSTopLevel.kt

@@ -0,0 +1,28 @@
+// IGNORE_BACKEND: JS
+// MODULE_KIND: COMMON_JS
+// !LANGUAGE: +JsAllowInvalidCharsIdentifiersEscaping
+
+// FILE: lib.kt
+@file:JsModule("lib")
+package lib
+
+external fun `@get something-invalid`(): String = definedExternally
+
+external val `some+value`: Int = definedExternally
+
+external object `+some+object%:` {
+    val foo: String = definedExternally
+}
+
+// FILE: main.kt
+import lib.`some+value`
+import lib.`@get something-invalid`
+import lib.`+some+object%:`
+
+fun box(): String {
+    assertEquals(42, `some+value`)
+    assertEquals("%%++%%", `+some+object%:`.foo)
+    assertEquals("something invalid", `@get something-invalid`())
+
+    return "OK"
+}