assert: fix .throws operator

assert.throws and assert.doesNotThrow set the operator to a
internal function. That was by accident and originally the operator
was undefined. This changes it to show "throws" or "doesNotThrow".
Backport-PR-URL: #23223
PR-URL: #17575
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

Author: BridgeAR

lib/assert.js

@@ -643,15 +643,18 @@ function innerThrows(shouldThrow, block, expected, message) {
 details+=` (${expected.name})`;
 }
 details+=message ? `: ${message}` : '.';
-fail(actual,expected,`Missing expected exception${details}`,fail);
+fail(actual,expected,`Missing expected exception${details}`,'throws');
 }
 if(expected&&expectedException(actual,expected)===false){
 throwactual;
 }
 }elseif(actual!==undefined){
 if(!expected||expectedException(actual,expected)){
 details=message ? `: ${message}` : '.';
-fail(actual,expected,`Got unwanted exception${details}`,fail);
+fail(actual,
+expected,
+`Got unwanted exception${details}`,
+'doesNotThrow');
 }
 throwactual;
 }

test/parallel/test-assert.js

@@ -463,10 +463,15 @@ assert.throws(() => { assert.ifError(new Error('test error')); },
 assert.doesNotThrow(()=>{assert.ifError(null);});
 assert.doesNotThrow(()=>{assert.ifError();});
 
-assert.throws(()=>{
-assert.doesNotThrow(makeBlock(thrower,Error),'user message');
-},/Gotunwantedexception:usermessage/,
-'a.doesNotThrow ignores user message');
+common.expectsError(
+()=>assert.doesNotThrow(makeBlock(thrower,Error),'user message'),
+{
+type: a.AssertionError,
+code: 'ERR_ASSERTION',
+operator: 'doesNotThrow',
+message: 'Got unwanted exception: user message\n[object Object]'
+}
+);
 
 // make sure that validating using constructor really works
 {
@@ -525,7 +530,8 @@ a.throws(makeBlock(thrower, TypeError), (err) => {
 ()=>{a.throws((noop));},
 common.expectsError({
 code: 'ERR_ASSERTION',
-message: /^Missingexpectedexception\.$/
+message: /^Missingexpectedexception\.$/,
+operator: 'throws'
 }));
 
 assert.throws(