Spacewar: Apply dex2oat optimizations

- Set only 4 threads to be utilized for dex2oat as dex2oat supports concurrent jobs since [1]. -
   Moreover, set only 4 threads to be utilized for boot image dex2oat as well.

[1]: 93c605c0d6

Change-Id: I9a531249de158f78b4a8b2289d949401dbf934e9

properties/vendor.prop

@@ -72,6 +72,12 @@ ro.bluetooth.a2dp_offload.supported=true
 ro.crypto.dm_default_key.options_format.version=2
 ro.crypto.volume.metadata.method=dm-default-key
 
+# Dex2oat
+dalvik.vm.dex2oat-cpu-set=4,5,6,7
+dalvik.vm.dex2oat-threads=4
+dalvik.vm.image-dex2oat-cpu-set=4,5,6,7
+dalvik.vm.image-dex2oat-threads=4
+ 
 # Display
 vendor.display.comp_mask=0
 vendor.display.disable_excl_rect=0