TestGetSystemCpuLoad - unexpected error value expected:<-1.0> but was:<-21.0>

[pshipton]

https://openj9-jenkins.osuosl.org/job/Test_openjdk11_j9_extended.functional_s390x_linux_Nightly_testList_0/675/
https://openj9-jenkins.osuosl.org/job/Test_openjdk11_j9_extended.functional_s390x_linux_Nightly_testList_1/674/
https://openj9-jenkins.osuosl.org/job/Test_openjdk11_j9_extended.functional_ppc64_aix_Nightly_testList_0/645
https://openj9-jenkins.osuosl.org/job/Test_openjdk11_j9_extended.functional_ppc64_aix_Nightly_testList_1/645/
https://openj9-jenkins.osuosl.org/job/Test_openjdk11_j9_extended.functional_aarch64_mac_Nightly_testList_1/397/
https://openj9-jenkins.osuosl.org/job/Test_openjdk11_j9_extended.functional_aarch64_linux_Nightly_testList_1/562
testCpuUtilization_testSingleCpuLoadObject_0

FAILED: testSingleCpuLoadObject
java.lang.AssertionError: unexpected error value expected:<-1.0> but was:<-21.0>
	at org.testng.AssertJUnit.fail(AssertJUnit.java:59)
	at org.testng.AssertJUnit.failNotEquals(AssertJUnit.java:364)
	at org.testng.AssertJUnit.assertEquals(AssertJUnit.java:126)
	at org.openj9.test.management.TestGetSystemCpuLoad.validateLoad(TestGetSystemCpuLoad.java:119)
	at org.openj9.test.management.TestGetSystemCpuLoad.testMxBeanImpl(TestGetSystemCpuLoad.java:74)
	at org.openj9.test.management.TestGetSystemCpuLoad.testSingleCpuLoadObject(TestGetSystemCpuLoad.java:50)

testCpuUtilization_testMxBean_0

FAILED: testMxBean
java.lang.AssertionError: unexpected error value expected:<-1.0> but was:<-21.0>
	at org.testng.AssertJUnit.fail(AssertJUnit.java:59)
	at org.testng.AssertJUnit.failNotEquals(AssertJUnit.java:364)
	at org.testng.AssertJUnit.assertEquals(AssertJUnit.java:126)
	at org.openj9.test.management.TestGetSystemCpuLoad.validateLoad(TestGetSystemCpuLoad.java:119)
	at org.openj9.test.management.TestGetSystemCpuLoad.testMxBeanImpl(TestGetSystemCpuLoad.java:74)
	at org.openj9.test.management.TestGetSystemCpuLoad.testMxBean(TestGetSystemCpuLoad.java:65)

[pshipton]

Related to #18451
@TobiAjila @thallium

OMRPORT_ERROR_INSUFFICIENT_DATA is -21

I don't think returning -21 is the expected behavior. I'm going to revert the change to avoid failing builds until it can be fixed.

This is only failing on jdk11 last night because the other builds started before the change was merged.

[pshipton]

Reverted via #18635

[thallium]

I fixed the PR to return -1 if only one data point is recorded.