trace processor: Export NaN/Infinity debug annotations to JSON properly
trace processor: Export NaN/Infinity debug annotations to JSON properly

Make sure debug annotations containing NaN/Infinity values are exported
properly to JSON. Note that these values are exported using quotes for
compatibility with Chrome's old exporter.

Change-Id: I07a10f11154154171fa2e7215a1cf64de0467da5
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto