fix(3901): handle out-of-bounds pos in skip trivia (#3914)

Author: a-tarasyuk

internal/scanner/scanner.go

@@ -2278,6 +2278,9 @@ func SkipTriviaEx(text string, pos int, options *SkipTriviaOptions) int {
 	canConsumeStar := false
 	// Keep in sync with couldStartTrivia
 	for {
+		if pos >= textLen {
+			return pos
+		}
 		ch, size := utf8.DecodeRuneInString(text[pos:])
 		switch ch {
 		case '\r':

testdata/baselines/reference/compiler/emitIncompleteDoStatement.errors.txt

@@ -0,0 +1,7 @@
+a.ts(1,3): error TS1109: Expression expected.
+
+
+==== a.ts (1 errors) ====
+    do
+      
+!!! error TS1109: Expression expected.

testdata/baselines/reference/compiler/emitIncompleteDoStatement.js

@@ -0,0 +1,10 @@
+//// [tests/cases/compiler/emitIncompleteDoStatement.ts] ////
+
+//// [a.ts]
+do
+
+//// [a.js]
+"use strict";
+do
+    ;
+while ();

testdata/baselines/reference/compiler/emitIncompleteDoStatement.symbols

@@ -0,0 +1,5 @@
+//// [tests/cases/compiler/emitIncompleteDoStatement.ts] ////
+
+=== a.ts ===
+
+do

testdata/baselines/reference/compiler/emitIncompleteDoStatement.types

@@ -0,0 +1,7 @@
+//// [tests/cases/compiler/emitIncompleteDoStatement.ts] ////
+
+=== a.ts ===
+do
+> : any
+> : any
+

testdata/tests/cases/compiler/emitIncompleteDoStatement.ts

@@ -0,0 +1,2 @@
+// @filename: a.ts
+do