test: add message verification on assert.throws

Add regular expression for error message validation to instances of
assert.throws() in test-assert.js.
PR-URL: #10890
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: tmeisenh

test/parallel/test-assert.js

@@ -90,11 +90,16 @@ assert.doesNotThrow(makeBlock(a.deepEqual, /a/g, /a/g));
 assert.doesNotThrow(makeBlock(a.deepEqual,/a/i,/a/i));
 assert.doesNotThrow(makeBlock(a.deepEqual,/a/m,/a/m));
 assert.doesNotThrow(makeBlock(a.deepEqual,/a/igm,/a/igm));
-assert.throws(makeBlock(a.deepEqual,/ab/,/a/));
-assert.throws(makeBlock(a.deepEqual,/a/g,/a/));
-assert.throws(makeBlock(a.deepEqual,/a/i,/a/));
-assert.throws(makeBlock(a.deepEqual,/a/m,/a/));
-assert.throws(makeBlock(a.deepEqual,/a/igm,/a/im));
+assert.throws(makeBlock(a.deepEqual,/ab/,/a/),
+/^AssertionError:\/ab\/deepEqual\/a\/$/);
+assert.throws(makeBlock(a.deepEqual,/a/g,/a/),
+/^AssertionError:\/a\/gdeepEqual\/a\/$/);
+assert.throws(makeBlock(a.deepEqual,/a/i,/a/),
+/^AssertionError:\/a\/ideepEqual\/a\/$/);
+assert.throws(makeBlock(a.deepEqual,/a/m,/a/),
+/^AssertionError:\/a\/mdeepEqual\/a\/$/);
+assert.throws(makeBlock(a.deepEqual,/a/igm,/a/im),
+/^AssertionError:\/a\/gimdeepEqual\/a\/im$/);
 
 {
 constre1=/a/g;