add support for try-statements with no catch block

javascript/ql/src/semmle/javascript/Expr.qll

@@ -251,11 +251,11 @@ class Expr extends @expr, ExprOrStmt, ExprOrType, AST::ValueNode {
    * causes an exception to be thrown.
    */
   DataFlow::Node getThrowsToNode() {
-    if exists(this.getEnclosingStmt().getEnclosingTryStmt())
+    if exists(this.getEnclosingStmt().getEnclosingTryCatchStmt())
     then
       result = DataFlow::parameterNode(this
               .getEnclosingStmt()
-              .getEnclosingTryStmt()
+              .getEnclosingTryCatchStmt()
               .getACatchClause()
               .getAParameter())
     else result = any(DataFlow::FunctionNode f | f.getFunction() = this.getContainer()).getExceptionalReturn()

javascript/ql/src/semmle/javascript/Stmt.qll

@@ -57,12 +57,13 @@ class Stmt extends @stmt, ExprOrStmt, Documentable {
   override predicate isAmbient() { hasDeclareKeyword(this) or getParent().isAmbient() }
   
   /**
-  * Gets the `try` statement containing this statement without crossing function
-  * boundaries or other `try ` statements.
+  * Gets the `try` statement with a catch block containing this statement without
+  * crossing function boundaries or other `try ` statements with catch blocks.
   */
-  TryStmt getEnclosingTryStmt() {
+  TryStmt getEnclosingTryCatchStmt() {
     getParentStmt+() = result.getBody() and
-    not exists(TryStmt mid |
+    exists(result.getACatchClause()) and
+    not exists(TryStmt mid | exists(mid.getACatchClause()) | 
       getParentStmt+() = mid.getBody() and mid.getParentStmt+() = result.getBody()
     )
   }