The problem is that currentcontextchecker.cxx is linked statically into 2
dynamic libraries, and with clang now using -fvisibility-ms-compat since
commit f0aa1a78 the ASAN complains about
ODR violation in testttols uno_test:

==1818==ERROR: AddressSanitizer: odr-violation (0x2aef08e9c600):
  [1] size=192 'vtable for testtools::bridgetest::CurrentContextChecker'
  testtools/source/bridgetest/currentcontextchecker.cxx
  [2] size=192 'vtable for testtools::bridgetest::CurrentContextChecker'
  testtools/source/bridgetest/currentcontextchecker.cxx

Change-Id: Ie705788dbf035f7a9f64878c6dcf3cec9b7e7ba1