Revert of [tickprocessor] Consider top of the stack as pc if it points to a...

Revert of [tickprocessor] Consider top of the stack as pc if it points to a code object. (patchset #1 id:1 of https://codereview.chromium.org/2822433002/ )

Reason for revert:
Seems to lead to more (completely) misattributed ticks

Original issue's description:
> [tickprocessor] Consider top of the stack as pc if it points to a code object.
>
> Previously, we would only consider it if it pointed to a full-code JS function.
> Thus we could miss both optimized functions and bytecode handlers if they
> called frame-less code.
>
> Review-Url: https://codereview.chromium.org/2822433002
> Cr-Commit-Position: refs/heads/master@{#44640}
> Committed: https://chromium.googlesource.com/v8/v8/+/4433ac299eae30b75357b05dab16d142d239f64e

TBR=jarin@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.

Review-Url: https://codereview.chromium.org/2844053003
Cr-Commit-Position: refs/heads/master@{#44921}

tools/tickprocessor.js

@@ -365,7 +365,7 @@ TickProcessor.prototype.processTick = function(pc,
     // Find out, if top of stack was pointing inside a JS function
     // meaning that we have encountered a frameless invocation.
     var funcEntry = this.profile_.findEntry(tos_or_external_callback);
-    if (!funcEntry) {
+    if (!funcEntry || !funcEntry.isJSFunction || !funcEntry.isJSFunction()) {
       tos_or_external_callback = 0;
     }
   }