Revert "test: disable fast API call count checks"

This reverts commit 6857dbc.

Author: targos

test/parallel/test-buffer-write-fast.js

@@ -41,7 +41,5 @@ testFastUtf8Write();
 
 if (common.isDebug) {
   const { getV8FastApiCallCount } = internalBinding('debug');
-  // TODO: the count should be 4. The function is optimized, but the fast
-  // API is not called.
-  assert.strictEqual(getV8FastApiCallCount('buffer.writeString'), 0);
+  assert(getV8FastApiCallCount('buffer.writeString'), 4);
 }

test/parallel/test-whatwg-url-canparse.js

@@ -34,9 +34,7 @@ assert.strictEqual(URL.canParse('https://example.org'), true);
 
   if (common.isDebug) {
     const { getV8FastApiCallCount } = internalBinding('debug');
-    // TODO: the counts should be 1. The function is optimized, but the fast
-    // API is not called.
-    assert.strictEqual(getV8FastApiCallCount('url.canParse'), 0);
-    assert.strictEqual(getV8FastApiCallCount('url.canParse.withBase'), 0);
+    assert.strictEqual(getV8FastApiCallCount('url.canParse'), 1);
+    assert.strictEqual(getV8FastApiCallCount('url.canParse.withBase'), 1);
   }
 }