When 'make test', many langtools test cases (1400+) and some other test cases (30+) will be affected by the local non-US environment, resulting in the test cases fail.

Jing Tian investigated[1] most of the test cases in which the fail was reported. The reason for the error was due to the non-US locale, but not because of the test cases itself.

Jing Tian added[2] a suggestion in the test doc, indicating that we can set the locale before 'make test', which will avoid many fail.

[1] https://mail.openjdk.java.net/pipermail/core-libs-dev/2019-March/059368.html
[2] http://cr.openjdk.java.net/~lzhai/8222444/webrev.03/