Track line and column numbers for expressions

Commit 73cc00e reduced the number of emitted source locations a great
deal but it resulted in at least one observable regression:

    export default async function f() {
         return "abc" + x
    }
    f() // ReferenceError should point to 2:20 but pointed to 1:1

Emit source locations for expressions again. Increases the average
number of source locations by about 15%. Non-scientifically tested
by counting source locations emitted when parsing the test suite
before and after.

No test because we currently cannot easily test stack traces coming
from module imports.

Fixes: #779

quickjs.c

@@ -19928,6 +19928,8 @@ static __exception int next_token(JSParseState *s)
     }
     s->token.col_num = max_int(1, s->mark - s->eol);
     s->buf_ptr = p;
+    s->last_line_num = s->token.line_num;
+    s->last_col_num = s->token.col_num;
 
     //    dump_token(s, &s->token);
     return 0;
@@ -24436,6 +24438,7 @@ static __exception int js_parse_expr_binary(JSParseState *s, int level,
         }
         if (next_token(s))
             return -1;
+        emit_source_loc(s);
         if (js_parse_expr_binary(s, level - 1, parse_flags))
             return -1;
         emit_op(s, opcode);

tests/test_builtin.js

@@ -7,12 +7,12 @@ function test_exception_source_pos()
     var e;
 
     try {
-        throw new Error(""); // line 10, column 15
+        throw new Error(""); // line 10, column 19
     } catch(_e) {
         e = _e;
     }
 
-    assert(e.stack.includes("test_builtin.js:10:15"));
+    assert(e.stack.includes("test_builtin.js:10:19"));
 }
 
 // Keep this at the top; it tests source positions.
@@ -36,7 +36,7 @@ function test_exception_prepare_stack()
     };
 
     try {
-        throw new Error(""); // line 39, column 15
+        throw new Error(""); // line 39, column 19
     } catch(_e) {
         e = _e;
     }
@@ -48,7 +48,7 @@ function test_exception_prepare_stack()
     assert(f.getFunctionName(), 'test_exception_prepare_stack');
     assert(f.getFileName().endsWith('test_builtin.js'));
     assert(f.getLineNumber(), 39);
-    assert(f.getColumnNumber(), 15);
+    assert(f.getColumnNumber(), 19);
     assert(!f.isNative());
 }
 
@@ -64,7 +64,7 @@ function test_exception_stack_size_limit()
     };
 
     try {
-        throw new Error(""); // line 67, column 15
+        throw new Error(""); // line 67, column 19
     } catch(_e) {
         e = _e;
     }
@@ -77,7 +77,7 @@ function test_exception_stack_size_limit()
     assert(f.getFunctionName(), 'test_exception_stack_size_limit');
     assert(f.getFileName().endsWith('test_builtin.js'));
     assert(f.getLineNumber(), 67);
-    assert(f.getColumnNumber(), 15);
+    assert(f.getColumnNumber(), 19);
     assert(!f.isNative());
 }