Revert "OpenJDK 11: Merging in java.util.StringJoiner"

This reverts commit 0dae862802373e996a789a772bfe3da2461cd3e7.

Reason for revert: Performance regression found due to this commit (b/201621581).

Bug: 201621581
Change-Id: Ia1a1d46d3c01e50d5a5dff634c435acf86d812a4
1 file changed