Bug 939385 (part 1) - Rename largestContiguousVMBlock as vsizeMaxContiguous.  r=froydnj.

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extra : rebase_source : 3c364af0442eeabd5951370792f1a467eaa86994
Bug 939385 (part 2) - Expose vsizeMaxContiguous to telemetry.  r=froydnj.

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extra : rebase_source : addf1db7cfe59fced1a8e8331034a28a2d801712
Bug 939385 (part 3) - Expose vsizeMaxContiguous to about:memory.  r=froydnj.

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extra : rebase_source : 77331283b56ddf28a137a0165ef9926d6e0f0f42
Bug 939385 (part 4) - Rename some distinguished amount functions.  r=froydnj.

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extra : rebase_source : 7aa40beaaf9f025f361d0a570a2f35d582a151c5