perfetto-ui: uncollapse tracks with heap profiles
perfetto-ui: uncollapse tracks with heap profiles

When opening a trace, show tracks with heap profile uncollapsed so the
users can quickly find heap profiles.

Test traces:
  ?s=5c348db9ad8f2d9025dcd0ba58c53643f456f66f1914cf23d7a988e139b68d6a

  ?s=fbb42d895c87b9a6673a03751ed9757c716b6027d6d7a79a5311106b102f

Change-Id: I7ad55ef8fb222c02a62c24fe6a034fd7ff29bc49
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto