Bug 1035570 (part 1) - DMD: Rename TraceRecord as Record. r=erahm.

DMD used to have "stack trace records" and "stack frame records". Bug 1013011
removed the latter, and now "stack trace record" and |TraceRecord| are a bit
unwieldy. This patch changes them to "heap block record" and |Record|.

--HG--
extra : rebase_source : 1d674db9866221f6a170d0eb05aa77fc9f4a1924
Bug 1035570 (part 2) - DMD: make output easier for machines to parse. r=erahm.

There are likely to be post-processing scripts for DMD added in the future. In
anticipation, this patch tweaks DMD's output to be a little more conducive to
machine parsing.

The basic idea is this:

- Lines beginning with '#' are comments and can be ignored, as can blank lines.

- All top level blocks consist of a string ending with '{', and then one or
  more indented lines, and then a closing '}' on its own line. Any multi-line
  things within a block are themselves enclosed in braces.

The diff for memory/replace/dmd/test-expected.dmd shows what this looks like in
practice.

It's a long way from a formal grammar or anything like that, but that would be
overkill. In this form it's quite easy to parse with simple scripts that just
do line-based regexp matching, rather than proper parsing. And it's still very
readable to humans, so I think it's a reasonable balance overall.

--HG--
extra : rebase_source : 64085babd79de3cce13295aa5f16a34dc3ad7697
Bug 1035570 (part 3) - DMD: Add DMDAnalyzeHeap(), a heap snapshot function. r=erahm,mccr8.

The patch also adds DMDAnalyzeReports() as a synonym for DMDReportAndDump(),
and deprecates the latter.

--HG--
extra : rebase_source : 651246aa7a0a301f804c124f25beb0e8ed6cd67f