test: minor fixups for REPL eval tests

The `process.on("exit")` event handlers are unnecessary, so it’s okay
to drop them.

PR-URL: https://github.com/nodejs/node/pull/11946
Ref: https://github.com/nodejs/node/pull/11871
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

test/parallel/test-repl-empty.js

@@ -9,7 +9,7 @@ const repl = require('repl');
   const options = {
     eval: common.mustCall((cmd, context) => {
       // Assertions here will not cause the test to exit with an error code
-      // so set a boolean that is checked in process.on('exit',...) instead.
+      // so set a boolean that is checked later instead.
       evalCalledWithExpectedArgs = (cmd === '\n');
     })
   };
@@ -23,7 +23,5 @@ const repl = require('repl');
     r.write('.exit\n');
   }
 
-  process.on('exit', () => {
-    assert(evalCalledWithExpectedArgs);
-  });
+  assert(evalCalledWithExpectedArgs);
 }

test/parallel/test-repl-eval.js

@@ -9,7 +9,7 @@ const repl = require('repl');
   const options = {
     eval: common.mustCall((cmd, context) => {
       // Assertions here will not cause the test to exit with an error code
-      // so set a boolean that is checked in process.on('exit',...) instead.
+      // so set a boolean that is checked later instead.
       evalCalledWithExpectedArgs = (cmd === 'function f() {}\n' &&
                                     context.foo === 'bar');
     })
@@ -29,7 +29,5 @@ const repl = require('repl');
     r.write('.exit\n');
   }
 
-  process.on('exit', () => {
-    assert(evalCalledWithExpectedArgs);
-  });
+  assert(evalCalledWithExpectedArgs);
 }