When building jdk11 with xlc16/legacy-xlc, we run into the fatal-calls in operator_new.cpp. This comes from iostream_init() calling into the new-operator :

operator_new.operator new(unsigned long)(size = 1152921504606839776), line 65 in "operator_new.cpp"
Iostream_init::Iostream_init()() at 0x900000000ed0f2c

jdk13/14 is not affected because it uses the xlc16/xlclang .
Only the non-PRODUCT builds are currently affected, because the calls to "fatal" in operator_new.cpp are only done in non-PRODUCT.