Add missing paren in "java -version" check

Change-Id: Id66e795423e8d25b48ac996956748a93060ea5db
Fix java version detection when _JAVA_OPTIONS is set.

_JAVA_OPTIONS is an environment variable that
can be used to affect the behavior of java and javac.
It is currently required to get Android to build on
some configurations, where the default Java heap size
is too small. Unfortunately, if _JAVA_OPTIONS is set,
both java and javac will output its value to the console
as the first line on every invocation, including trivial
ones like java -version. This will confuse main.mk’s
version detection, which only looks at the first line of
output. Tweak the version detection to run grep before
head, so that the _JAVA_OPTIONS line is filtered by the grep.

Change-Id: I69aee52b56d27711b7d3087ec6b3ebab07ffc3af
Bring main.mk in sync with master.

These lines were removed in aosp in commit e2d27887b
but a bad merge conflict resolution left them in master.

Subsequent changes on master started using these variables
so they're being brought back.

Change-Id: Ic8f3c295130c47eb0d66057880f9d4f70c89af94
Merge "Add missing paren in "java -version" check" into kitkat
Merge "Fix java version detection when _JAVA_OPTIONS is set." into kitkat
Merge "Bring main.mk in sync with master." into kitkat