Improve line info construction (#4718)

- Simplify small encoding
- Better line info for some corner cases

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

tests/jerry/eval.js

@@ -159,3 +159,13 @@ function f7() {
   eval("assert(x()() === 5); function y() { return 5 } assert(x()() === 5)");
 }
 f7()
+
+eval(" ");
+eval("(function () {})")
+
+try {
+  /* Only fails in ES5.1 */
+  eval("()=>0")
+} catch (e) {
+  assert(e instanceof SyntaxError)
+}

tests/unit-core/test-backtrace.c

@@ -159,14 +159,14 @@ class_backtrace_callback (jerry_backtrace_frame_t *frame_p, /* frame information
   {
     TEST_ASSERT (jerry_backtrace_is_strict (frame_p));
     TEST_ASSERT (location_p->line == 3);
-    TEST_ASSERT (location_p->column == 12);
+    TEST_ASSERT (location_p->column == 14);
     return false;
   }
 
   TEST_ASSERT (frame_index == 2);
   TEST_ASSERT (jerry_backtrace_is_strict (frame_p));
   TEST_ASSERT (location_p->line == 2);
-  TEST_ASSERT (location_p->column == 5);
+  TEST_ASSERT (location_p->column == 7);
   return false;
 } /* class_backtrace_callback */