[js] revert recent String.substr and StringTools.trim changes (see #4365 and 7d7adba63563f4b805f613d602cfc28b095f6bb1)

std/StringTools.hx

@@ -244,13 +244,11 @@ class StringTools {
 
 		This is a convenience function for `ltrim(rtrim(s))`.
 	**/
-	public #if (cs || java || (js && js_es5)) inline #end static function trim( s : String ) : String {
+	public #if (cs || java) inline #end static function trim( s : String ) : String {
 		#if cs
 		return untyped s.Trim();
 		#elseif java
 		return untyped s.trim();
-		#elseif (js && js_es5)
-		return untyped s.trim();
 		#else
 		return ltrim(rtrim(s));
 		#end

std/js/_std/String.hx

@@ -36,13 +36,9 @@
 		return untyped HxOverrides.cca(this, index);
 	}
 
-	#if js_es5
-	function substr( pos : Int, ?len : Int ) : String;
-	#else
 	inline function substr( pos : Int, ?len : Int ) : String {
 		return untyped HxOverrides.substr(this, pos, len);
 	}
-	#end
 
 	static function fromCharCode( code : Int ) : String;
 }

tests/unit/src/unit/TestBasetypes.hx

@@ -64,9 +64,7 @@ class TestBasetypes extends Test {
 		eq(sentence.substr(-5), "jugs.");
 		eq(sentence.substr(-42), sentence);
 		eq(sentence.substr(4, 0), "");
-		#if !js_es5
 		eq(sentence.substr(0, -36), "Pack");
-		#end
 
 		// null should not be swallowed
 		eq("hello" +null, "hellonull");

tests/unit/src/unitstd/String.unit.hx

@@ -120,10 +120,8 @@ s.substr(0, 0) == "";
 s.substr(0, 1) == "x";
 s.substr(0, 2) == "xf";
 s.substr(0, 100) == "xfooxfooxxbarxbarxx";
-#if !js_es5
 s.substr(0, -1) == "xfooxfooxxbarxbarx";
 s.substr(0, -2) == "xfooxfooxxbarxbar";
-#end
 //s.substr(1, -2) == "fooxfooxxbarxbar";
 //s.substr(2, -2) == "ooxfooxxbarxbar";
 s.substr(0, -100) == "";