Run jtreg:jdk/java/lang/ProcessBuilder/Basic.java on AIX.

The test fails with following exception:
-----------------------
java.lang.Exception: Stack trace
        at java.base/java.lang.Thread.dumpStack(Thread.java:1375)
        at Basic.fail(Basic.java:2825)
        at Basic.fail(Basic.java:2826)
        at Basic.equal(Basic.java:2832)
        at Basic.realMain(Basic.java:1886)
        at Basic.main(Basic.java:2835)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
        at java.base/java.lang.reflect.Method.invoke(Method.java:577)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
        at java.base/java.lang.Thread.run(Thread.java:828)
Incorrect handling of envstrings containing NULs
java.lang.Exception: Stack trace
        at java.base/java.lang.Thread.dumpStack(Thread.java:1375)
        at Basic.fail(Basic.java:2825)
        at Basic.fail(Basic.java:2826)
        at Basic.check(Basic.java:2829)
        at Basic.realMain(Basic.java:1940)
        at Basic.main(Basic.java:2835)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
        at java.base/java.lang.reflect.Method.invoke(Method.java:577)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
        at java.base/java.lang.Thread.run(Thread.java:828)
java.lang.AssertionError: Some tests failed
        at Basic.main(Basic.java:2837)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
        at java.base/java.lang.reflect.Method.invoke(Method.java:577)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
        at java.base/java.lang.Thread.run(Thread.java:828)
-----------------------

According to my investigation, this issue was happened after following change was applied.
JDK-8272600: (test) Use native "sleep" in Basic.java

test.nativepath value was added into AIX's LIBPATH during running this testcase.
On AIX, test.nativepath value should be removed from LIBPATH value before comparing the values.