Revert of Revert of [turbofan] Small fixes to PipelineStatistics. Collect...

Revert of Revert of [turbofan] Small fixes to PipelineStatistics. Collect statistics in tests. (patchset #1 id:1 of https://codereview.chromium.org/1119963003/)

Reason for revert:
Revert didn't fix the problem. Maybe it was another CL.

Original issue's description:
> Revert of [turbofan] Small fixes to PipelineStatistics. Collect statistics in tests. (patchset #1 id:1 of https://codereview.chromium.org/1122753002/)
>
> Reason for revert:
> [Sheriff] Speculative revert for breaking arm64 nosnap:
> http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20nosnap%20-%20debug%20-%202/builds/2314
>
> Original issue's description:
> > [turbofan] Small fixes to PipelineStatistics. Collect statistics in tests.
> >
> > R=bmeurer@chromium.org
> > BUG=
> >
> > Committed: https://crrev.com/9833844268357590243732a53e2a7fc0dc5fcc9e
> > Cr-Commit-Position: refs/heads/master@{#28192}
>
> TBR=bmeurer@chromium.org,titzer@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
>
> Committed: https://crrev.com/d0ed8940fc6c995eba57149b8e8cb214001e8381
> Cr-Commit-Position: refs/heads/master@{#28205}

TBR=bmeurer@chromium.org,titzer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1126603002

Cr-Commit-Position: refs/heads/master@{#28207}

src/compiler/pipeline-statistics.cc

@@ -50,7 +50,7 @@ PipelineStatistics::PipelineStatistics(CompilationInfo* info,
       source_size_(0),
       phase_kind_name_(NULL),
       phase_name_(NULL) {
-  if (!info->shared_info().is_null()) {
+  if (info->has_shared_info()) {
     source_size_ = static_cast<size_t>(info->shared_info()->SourceSize());
     SmartArrayPointer<char> name =
         info->shared_info()->DebugName()->ToCString();

src/compiler/pipeline.cc

@@ -1139,6 +1139,12 @@ Handle<Code> Pipeline::GenerateCodeForTesting(CompilationInfo* info,
   // Construct a pipeline for scheduling and code generation.
   ZonePool zone_pool;
   PipelineData data(&zone_pool, info, graph, schedule);
+  SmartPointer<PipelineStatistics> pipeline_statistics;
+  if (FLAG_turbo_stats) {
+    pipeline_statistics.Reset(new PipelineStatistics(info, &zone_pool));
+    pipeline_statistics->BeginPhaseKind("test codegen");
+  }
+
   Pipeline pipeline(info);
   pipeline.data_ = &data;
   if (data.schedule() == nullptr) {