Bug 1473588: Upgrade minimum ICU version to ICU 63. r=jorendorff

build/autoconf/icu.m4

@@ -14,7 +14,7 @@ MOZ_ARG_WITH_BOOL(system-icu,
     MOZ_SYSTEM_ICU=1)
 
 if test -n "$MOZ_SYSTEM_ICU"; then
-    PKG_CHECK_MODULES(MOZ_ICU, icu-i18n >= 59.1)
+    PKG_CHECK_MODULES(MOZ_ICU, icu-i18n >= 63.1)
     CFLAGS="$CFLAGS $MOZ_ICU_CFLAGS"
     CXXFLAGS="$CXXFLAGS $MOZ_ICU_CFLAGS"
     AC_DEFINE(MOZ_SYSTEM_ICU)

js/src/tests/jstests.list

@@ -450,9 +450,6 @@ skip script test262/intl402/RelativeTimeFormat/prototype/format/pl-pl-style-long
 skip script test262/intl402/RelativeTimeFormat/prototype/format/pl-pl-style-narrow.js
 skip script test262/intl402/RelativeTimeFormat/prototype/format/pl-pl-style-short.js
 
-# https://bugzilla.mozilla.org/show_bug.cgi?id=1473588
-skip script test262/intl402/RelativeTimeFormat/prototype/format/unit-plural.js
-
 
 ###########################################################
 # Tests disabled due to issues in test262 importer script #