In
test/hotspot/jtreg/serviceability/jvmti/StartPhase/AllowedFunctions/libAllowedFunctions.c,
around line 108,
some bits are tested to see if they are true. The test used will always
return false:

    (status & JVMTI_CLASS_STATUS_INITIALIZED) == 1 ||(status &
    JVMTI_CLASS_STATUS_ERROR) == 1) {

From the build log:

$ make all
Building target 'all' in configuration 'linux-x86_64-server-release'
Skip building of Graal unit tests because 3rd party libraries directory is not specified
Skip building of Graal unit tests because 3rd party libraries directory is not specified
Creating support/test/hotspot/jtreg/native/lib/libAllowedFunctions.so from 1 file(s)
/home/stooke/dev/openjdk/jdk12/test/hotspot/jtreg/serviceability/jvmti/StartPhase/AllowedFunctions/libAllowedFunctions.c: In function ‘print_class_status’:
/home/stooke/dev/openjdk/jdk12/test/hotspot/jtreg/serviceability/jvmti/StartPhase/AllowedFunctions/libAllowedFunctions.c:113:51: error: bitwise comparison always evaluates to false[-Werror=tautological-compare]
         (status & JVMTI_CLASS_STATUS_INITIALIZED) == 1 ||
                                                   ^~
/home/stooke/dev/openjdk/jdk12/test/hotspot/jtreg/serviceability/jvmti/StartPhase/AllowedFunctions/libAllowedFunctions.c:114:51: error: bitwise comparison always evaluates to false[-Werror=tautological-compare]
         (status & JVMTI_CLASS_STATUS_ERROR) == 1) {
                                                   ^~
cc1: all warnings being treated as errors
gmake[3]: *** [JtregNativeHotspot.gmk:1518: /home/stooke/dev/openjdk/jdk12/build/linux-x86_64-server-release/support/test/hotspot/jtreg/native/support/libAllowedFunctions/libAllowedFunctions.o] Error 1
gmake[3]: *** Waiting for unfinished jobs....
gmake[2]: *** [make/Main.gmk:503: build-test-hotspot-jtreg-native] Error 2

ERROR: Build failed for target 'all' in configuration 'linux-x86_64-server-release' (exit code 2)

=== Output from failing command(s) repeated here ===
* For target support_test_hotspot_jtreg_native_support_libAllowedFunctions_libAllowedFunctions.o:
/home/stooke/dev/openjdk/jdk12/test/hotspot/jtreg/serviceability/jvmti/StartPhase/AllowedFunctions/libAllowedFunctions.c: In function ‘print_class_status’:
/home/stooke/dev/openjdk/jdk12/test/hotspot/jtreg/serviceability/jvmti/StartPhase/AllowedFunctions/libAllowedFunctions.c:113:51: error: bitwise comparison always evaluates to false[-Werror=tautological-compare]
         (status & JVMTI_CLASS_STATUS_INITIALIZED) == 1 ||
                                                   ^~
/home/stooke/dev/openjdk/jdk12/test/hotspot/jtreg/serviceability/jvmti/StartPhase/AllowedFunctions/libAllowedFunctions.c:114:51: error: bitwise comparison always evaluates to false[-Werror=tautological-compare]
         (status & JVMTI_CLASS_STATUS_ERROR) == 1) {
                                                   ^~
cc1: all warnings being treated as errors

* All command lines available in /home/stooke/dev/openjdk/jdk12/build/linux-x86_64-server-release/make-support/failure-logs.
=== End of repeated output ===

No indication of failed target found.
Hint: Try searching the build log for '] Error'.
Hint: See doc/building.html#troubleshooting for assistance.