message: More string fixes
diff: @@ -211,10 +211,10 @@ def doBuildInDocker(String buildType, String sanitizeMode='', boolean enableAsse
  def targetBuildType = "${buildType}"
  def cmakeFlags = '-DREALM_BUILD_LIB_ONLY=ON'
  if (sanitizeMode.contains('thread')) {
  - cmakeFlags = ' -D REALM_TSAN=ON'
  + cmakeFlags += ' -D REALM_TSAN=ON'
  targetBuildType = "${targetBuildType}+TSAN"
  } else if (sanitizeMode.contains('address')) {
  - cmakeFlags = ' -D REALM_ASAN=ON'
  + cmakeFlags += ' -D REALM_ASAN=ON'
  targetBuildType = "${targetBuildType}+ASAN"
  }
  if (enableAssertions) {
  