test_runner: ignore unmappes lines for coverage

lib/internal/test_runner/coverage.js

@@ -3,6 +3,7 @@ const {
   ArrayFrom,
   ArrayPrototypeMap,
   ArrayPrototypePush,
+  ArrayPrototypeForEach,
   JSONParse,
   MathFloor,
   MathMax,
@@ -365,6 +366,12 @@ class TestCoverage {
         }
       }
       const sourceMap = new SourceMap(data, { __proto__: null, lineLengths });
+      const linesToCover = new Set();
+
+      for(let mapping of sourceMap[kMappings]) {
+        const { 3: originalLine } = mapping
+        linesToCover.add(originalLine + 1);
+      }
 
       for (let j = 0; j < functions.length; ++j) {
         const { ranges, functionName, isBlockCoverage } = functions[j];
@@ -413,6 +420,13 @@ class TestCoverage {
           // No mappable ranges. Skip the function.
           continue;
         }
+
+        ArrayPrototypeForEach(this.getLines(newUrl), (mappedLine) => {
+          if (!linesToCover.has(mappedLine.line)) {
+            mappedLine.ignore = true;
+          }
+        });
+
         const newScript = newResult.get(newUrl) ?? { __proto__: null, url: newUrl, functions: [] };
         ArrayPrototypePush(newScript.functions, { __proto__: null, functionName, ranges: newRanges, isBlockCoverage });
         newResult.set(newUrl, newScript);