Remove assert.deepEqual

The `assert.deepEqual` utility method was originally implemented in
support of two tests for the "RegExp Match Indices" proposal [1]. In the
years since that time, it has been referenced by one additional test,
where it is interchangeable with the considerably simpler
`assert.compareArray`.

Refactor the RegExp tests to use a simpler inline helper function that
verifies the same semantics and preserves meaningful error messages.

[1] tc39#2309

test/built-ins/Error/constructor.js

@@ -12,7 +12,7 @@ info: |
 
 esid: sec-error-message
 features: [error-cause]
-includes: [deepEqual.js]
+includes: [compareArray.js]
 ---*/
 
 var message = "my-message";
@@ -34,4 +34,4 @@ new Error(
   },
 );
 
-assert.deepEqual(sequence, [ "toString", "cause" ], "accessing own properties on sequence");
+assert.compareArray(sequence, [ "toString", "cause" ], "accessing own properties on sequence");

test/built-ins/RegExp/match-indices/indices-array-non-unicode-match.js

@@ -3,7 +3,7 @@
 
 /*---
 description: Basic matching cases with non-unicode matches.
-includes: [compareArray.js, propertyHelper.js, deepEqual.js]
+includes: [compareArray.js, propertyHelper.js]
 esid: sec-regexpbuiltinexec
 features: [regexp-match-indices]
 info: |
@@ -31,13 +31,21 @@ info: |
       b. Perform ! CreateDataProperty(_A_, `"indices"`, _indicesArray_).
 ---*/
 
-assert.deepEqual([[1, 2], [1, 2]], "bab".match(/(a)/d).indices);
-assert.deepEqual([[0, 3], [1, 2]], "bab".match(/.(a)./d).indices);
-assert.deepEqual([[0, 3], [1, 2], [2, 3]], "bab".match(/.(a)(.)/d).indices);
-assert.deepEqual([[0, 3], [1, 3]], "bab".match(/.(\w\w)/d).indices);
-assert.deepEqual([[0, 3], [0, 3]], "bab".match(/(\w\w\w)/d).indices);
-assert.deepEqual([[0, 3], [0, 2], [2, 3]], "bab".match(/(\w\w)(\w)/d).indices);
-assert.deepEqual([[0, 2], [0, 2], undefined], "bab".match(/(\w\w)(\W)?/d).indices);
+function spread(indices) {
+  if (indices.length === 2) {
+    return indices[0].concat("x").concat(indices[1]);
+  } else if (indices.length === 3) {
+    return indices[0].concat("x").concat(indices[1]).concat("x").concat(indices[2]);
+  }
+}
+
+assert.compareArray([1, 2, "x", 1, 2], spread("bab".match(/(a)/d).indices));
+assert.compareArray([0, 3, "x", 1, 2], spread("bab".match(/.(a)./d).indices));
+assert.compareArray([0, 3, "x", 1, 2, "x", 2, 3], spread("bab".match(/.(a)(.)/d).indices));
+assert.compareArray([0, 3, "x", 1, 3], spread("bab".match(/.(\w\w)/d).indices));
+assert.compareArray([0, 3, "x", 0, 3], spread("bab".match(/(\w\w\w)/d).indices));
+assert.compareArray([0, 3, "x", 0, 2, "x", 2, 3], spread("bab".match(/(\w\w)(\w)/d).indices));
+assert.compareArray([0, 2, "x", 0, 2, "x", undefined], spread("bab".match(/(\w\w)(\W)?/d).indices));
 
 let groups = /(?<a>.)(?<b>.)(?<c>.)\k<c>\k<b>\k<a>/d.exec("abccba").indices.groups;
 assert.compareArray([0, 1], groups.a);