src,test: support node.js >= 8

[bnoordhuis]

This depends on changes that haven't been upstreamed yet. Diff for the eager:

diff --git a/deps/v8/tools/gen-postmortem-metadata.py b/deps/v8/tools/gen-postmortem-metadata.py
index 8857134..8f8d8a1 100644
--- a/deps/v8/tools/gen-postmortem-metadata.py
+++ b/deps/v8/tools/gen-postmortem-metadata.py
@@ -99,6 +99,22 @@ consts_misc = [
         'value': 'kAccessor' },
     { 'name': 'prop_kind_mask',
         'value': 'PropertyDetails::KindField::kMask' },
+    { 'name': 'prop_location_Descriptor',
+        'value': 'kDescriptor' },
+    { 'name': 'prop_location_Field',
+        'value': 'kField' },
+    { 'name': 'prop_location_mask',
+        'value': 'PropertyDetails::LocationField::kMask' },
+    { 'name': 'prop_location_shift',
+        'value': 'PropertyDetails::LocationField::kShift' },
+    { 'name': 'prop_attributes_NONE', 'value': 'NONE' },
+    { 'name': 'prop_attributes_READ_ONLY', 'value': 'READ_ONLY' },
+    { 'name': 'prop_attributes_DONT_ENUM', 'value': 'DONT_ENUM' },
+    { 'name': 'prop_attributes_DONT_DELETE', 'value': 'DONT_DELETE' },
+    { 'name': 'prop_attributes_mask',
+        'value': 'PropertyDetails::AttributesField::kMask' },
+    { 'name': 'prop_attributes_shift',
+        'value': 'PropertyDetails::AttributesField::kShift' },
     { 'name': 'prop_index_mask',
         'value': 'PropertyDetails::FieldIndexField::kMask' },
     { 'name': 'prop_index_shift',

Verified locally to work with node.js v4, v6, v7 and v8.0.0-pre and is clang-format clean.

[hhellyer]

I'm going to have a proper look at this, I need to update my Node built tree and put your gen-postmortem-metadata.py patch in first though. (Didn't want you to think this is being ignored!)

[hhellyer]

Ok, doing the updates took less time than expected. :-)
LGTM with the updated gen-postmortem-metadata.py in the build.

@indutny - Should we merge this or wait until Node 8 releases?

[bnoordhuis]

Dropped the single-character variable names. The V8 patch landed in node.js master, see nodejs/node#12722. Barring objections, I'll merge this tomorrow.