Remove empty expression in expression statement with top level await (#630)

Eats the semi-colon.

This doesn't compile (edit: doesn't compile the code in the tests) though because the target of that folder is ES2015. Also, this is kind of strange for me to put the tests in the "typescript" folder. Should we create something more general?

You can take over this PR if you'd like!

ecmascript/parser/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "swc_ecma_parser"
-version = "0.18.0"
+version = "0.18.1"
 authors = ["강동윤 <kdy1997.dev@gmail.com>"]
 license = "Apache-2.0/MIT"
 repository = "https://github.com/swc-project/swc.git"

ecmascript/parser/src/parser/stmt.rs

@@ -100,6 +100,7 @@ impl<'a, I: Tokens> Parser<'a, I> {
             }
 
             let expr = self.parse_await_expr()?;
+            eat!(';');
 
             let span = span!(start);
             return Ok(Stmt::Expr(ExprStmt { span, expr }));

tests/projects.rs

@@ -352,3 +352,12 @@ fn issue_605() {
 
     assert!(f.contains("Object.keys(_c)"));
 }
+
+#[test]
+fn await_expr() {
+    let f = file("tests/projects/await-expression/input.js").unwrap();
+    println!("{}", f);
+
+    assert!(f.contains("await"));
+    assert!(f.contains("test"));
+}

tests/projects/await-expression/.swcrc

@@ -0,0 +1,9 @@
+{
+  "jsc": {
+    "target": "es2017",
+    "parser": {
+        "syntax": "ecmascript",
+        "topLevelAwait": true
+    }
+  }
+}

tests/projects/await-expression/input.js

@@ -0,0 +1 @@
+await   test   ;