Revert "Fix for PR32990"

This reverts commit r321239. It broke the Chromium DLL build:

[8834/50217] LINK(DLL) icui18n.dll icui18n.dll.lib icui18n.dll.pdb
FAILED: icui18n.dll icui18n.dll.lib icui18n.dll.pdb
zrule.obj : error LNK2001: unresolved external symbol
"__declspec(dllimport) public: void __cdecl icu_60::UnicodeString::`vbase destructor'(void)"
(__imp_??_DUnicodeString@icu_60@@QEAAXXZ)

llvm-svn: 321298