[debugger] implement inspector-facing API for code coverage.

test/mjsunit/code-coverage-precise.js

Index: test/mjsunit/code-coverage-precise.js
diff --git a/test/mjsunit/code-coverage-precise.js b/test/mjsunit/code-coverage-precise.js
index 344e2f5397d3154ba5b8ccb33e3e493ba3706f55..a25542dae968c6803fa78682fb19c9a3d6ff2805 100644
--- a/test/mjsunit/code-coverage-precise.js
+++ b/test/mjsunit/code-coverage-precise.js
@@ -70,7 +70,7 @@ TestCoverage(
 (function f() {})();
 `,
 `
-[([function f() {}](f:1))();](anonymous:1)
+[([function f() {}](f:1))();](:1)
 `
 );
 
@@ -86,7 +86,7 @@ for (var i = 0; i < 10; i++) {
 [for (var i = 0; i < 10; i++) {
   let f = [() => 1](f:5);
   i += f();
-}](anonymous:1)
+}](:1)
 `
 );