drop trailing trivia prior to rescanning it

src/services/formatting/formattingScanner.ts

@@ -187,6 +187,9 @@ module ts.formatting {
             }
 
             // consume trailing trivia
+            if (trailingTrivia) {
+                trailingTrivia = undefined;
+            }
             while(scanner.getStartPos() < endPos) {
                 currentToken = scanner.scan();
                 if (!isTrivia(currentToken)) {

tests/cases/fourslash/formatTemplateLiteral.ts

@@ -1,7 +1,13 @@
 /// <reference path="fourslash.ts"/>
 ////var x = `sadasdasdasdasfegsfd
 /////*1*/rasdesgeryt35t35y35 e4 ergt er 35t 3535 `;
+////var y = `1${2}/*2*/3`;
+
 
 goTo.marker("1");
 edit.insert("\r\n"); // edit will trigger formatting - should succeeed
 
+goTo.marker("2");
+edit.insert("\r\n");
+verify.indentationIs(0);
+verify.currentLineContentIs("3`;")