Cherry-pick: ICU-20350 Fix DecimalFormatSymbols.setPatternForCurrencySpacing affecting the value across instances

According to the upstream bug
https://unicode-org.atlassian.net/browse/ICU-20350?focusedCommentId=63142#comment-63142,
it's a regression in ICU 58.

Bug: 116850744
Test: CtsIcuTestCases
Change-Id: Ida6b42dad692b7d31df94c788d43a6d41d728982
4 files changed