[TESTBUG] vmTestbase/jit/tiered/Test.java failed when TieredCompilation is disabled

When TieredCompilation is disabled, the test will fail. The cause is that the test failed to detect "-XX:+TieredCompilation not supported":

STDERR:
 stdout: [];
 stderr: [OpenJDK 64-Bit Server VM warning: -XX:+TieredCompilation not supported in this VM
openjdk version "15-internal" 2020-09-15
OpenJDK Runtime Environment (fastdebug build 15-internal+0-adhoc.loongson.jdk-mips)
OpenJDK 64-Bit Server VM (fastdebug build 15-internal+0-adhoc.loongson.jdk-mips, mixed mode)
]
 exitValue = 0

java.lang.RuntimeException: '^[0-9.]+: \[compile level=\d' missing from stdout

        at jdk.test.lib.process.OutputAnalyzer.stdoutShouldMatch(OutputAnalyzer.java:324)
        at vmTestbase.jit.tiered.Test.main(Test.java:66)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:564)
        at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:298)
        at java.base/java.lang.Thread.run(Thread.java:832)

JavaTest Message: Test threw exception: java.lang.RuntimeException
JavaTest Message: shutting down test