Add --max-old-space-size=8192 argument to bin/kibana script to avoid running out of memory during optimize step.

[cjcenizal]

I started consistently getting these errors every time I tried to build Kibana:

<--- Last few GCs --->

   52512 ms: Mark-sweep 941.8 (1311.1) -> 931.6 (1287.5) MB, 368.5 / 0.0 ms [allocation failure] [GC in old space requested].
   52853 ms: Mark-sweep 931.6 (1287.5) -> 922.6 (1272.5) MB, 341.1 / 0.0 ms [allocation failure] [GC in old space requested].
   53235 ms: Mark-sweep 922.6 (1272.5) -> 922.1 (1193.5) MB, 381.8 / 0.0 ms [last resort gc].
   53563 ms: Mark-sweep 922.1 (1193.5) -> 922.1 (1160.5) MB, 327.8 / 0.0 ms [last resort gc].


<--- JS stacktrace --->

==== JS stack trace =========================================

Security context: 0x1400a5cfb39 <JS Object>
    1: SparseJoinWithSeparatorJS(aka SparseJoinWithSeparatorJS) [native array.js:~75] [pc=0x133f2225ba77] (this=0x1400a504381 <undefined>,w=0x1fcf0266b191 <JS Array[55178]>,F=0x39dab2fae461 <JS Array[55178]>,x=55178,I=0x1400a5b46c9 <JS Function ConvertToString (SharedFunctionInfo 0x1400a552dc9)>,J=0x39dab2fdb779 <String[6]\: ,\n    >)
    2: DoJoin(aka DoJoin) [native array.js:~129] [pc=0x133f22...

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
 1: node::Abort() [/Users/cjcenizal/.nvm/versions/node/v6.10.2/bin/node]
 2: node::FatalException(v8::Isolate*, v8::Local<v8::Value>, v8::Local<v8::Message>) [/Users/cjcenizal/.nvm/versions/node/v6.10.2/bin/node]
 3: v8::internal::V8::FatalProcessOutOfMemory(char const*, bool) [/Users/cjcenizal/.nvm/versions/node/v6.10.2/bin/node]
 4: v8::internal::Factory::NewRawTwoByteString(int, v8::internal::PretenureFlag) [/Users/cjcenizal/.nvm/versions/node/v6.10.2/bin/node]
 5: v8::internal::Runtime_SparseJoinWithSeparator(int, v8::internal::Object**, v8::internal::Isolate*) [/Users/cjcenizal/.nvm/versions/node/v6.10.2/bin/node]
 6: 0x133f1e2092a7

By adding this flag, we allow the V8 engine to allocate 8GB of memory (I think). When I added this flag, I stopped encountering these errors.

[cjcenizal]

I just found #6727. Maybe we should implement the solution it requests instead of this?

Also related:

• Lets talk about v8's memory settings #5595
• Limit memory overhead #6822 (comment)
• Default NodeJS max heap limit to 250MB. Override by setting NODE_OPTIONS #5451 (decision not to set a default, as this PR does)

I wonder if I should just close this and instead set this option via the command line when I run Kibana?