Fixed bugs in return type of CatchClauseEvaluation algorithm

[jhnaldo]

We found the return type bug in the syntax-directed operation: 14.15.2 Runtime semantics: CatchClauseEvaluation via ESMeta type analyzer.

Currently, the type of CatchClauseEvaluation is defined as follows:

       Runtime Semantics: CatchClauseEvaluation (
         _thrownValue_: an ECMAScript language value,
       ): either a normal completion containing an ECMAScript language value or an abrupt completion

However, I think its return type should contain a normal completion containing ~empty~.

In step 7 for Catch : `catch` `(` CatchParameter `)` Block case, the variable B stores the result of Evaluation of |Block|. According to 14.2.2 Runtime Semantics: Evaluation, the variable B might be a normal completion containing ~empty~. Then, step 9 returns the value stored in the variable B.

Similarly, in step 1 for Catch : `catch` Block case, it directly returns the result of Evaluation of |Block|.

Therefore, I suggest extending its return type as follows:

         Runtime Semantics: CatchClauseEvaluation (
           _thrownValue_: an ECMAScript language value,
-        ): either a normal completion containing an ECMAScript language value or an abrupt completion
+        ): either a normal completion containing either an ECMAScript language value or ~empty~, or an abrupt completion

[jhnaldo]

I will request a new PR.

[ljharb]

What was wrong with this one?

[jhnaldo]

Since our tool detected other similar bugs, I wanted to update this PR. But, I accidentally removed my branch. So, I reopened another PR with other detected bugs: #2924.