Make javac.py assume UTF-8 encoding always
Make javac.py assume UTF-8 encoding always

My understanding is that by-default javac
pulls encoding from the user's environment
http://stackoverflow.com/questions/9661935/how-to-change-the-defaults-system-java-encode-form-in-windows
http://stackoverflow.com/questions/11343828/file-encoding-has-no-effect-lc-all-environment-variable-does-it
which is wrong for Chromium where all of our
source files are known to be UTF-8, regardless
of what the user has set in their environment.

In my case I was using Chrome Remote Desktop
to connect to my linux machine and for
whatever reason LANG was missing from the
resulting environment.  After this patch
mojo_shell builds correctly for Android again.

BUG=419378

Review URL: https://codereview.chromium.org/869673002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#313432}

Fireblend/chromium-crosswalk,Just-D/chromium-1,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Fireblend/chromium-crosswalk,Just-D/chromium-1,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,fujunwei/chromium-crosswalk,Pluto-tv/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,Fireblend/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,fujunwei/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,axinging/chromium-crosswalk,chuan9/chromium-crosswalk,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,fujunwei/chromium-crosswalk,chuan9/chromium-crosswalk,fujunwei/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,ltilve/chromium,Pluto-tv/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,chuan9/chromium-crosswalk,Fireblend/chromium-crosswalk,ltilve/chromium,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,Chilledheart/chromium,chuan9/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,ltilve/chromium,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,fujunwei/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,chuan9/chromium-crosswalk,Just-D/chromium-1,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk