SecureRandom tests timeout on aarch64

The following tests failed in the JDK15 CI:

sun/security/provider/SecureRandom/StrongSecureRandom.java
sun/security/provider/SecureRandom/SHA1PRNGReseed.java
sun/security/provider/SecureRandom/AbstractDrbg/SpecTest.java

on aarch64 in Tier2 testing.

Here's a snippet from the StrongSecureRandom.java log file:

#section:main
----------messages:(8/227)----------
command: main StrongSecureRandom
reason: User specified action: run main StrongSecureRandom
Mode: agentvm
Agent id: 3
Timeout refired 480 times
Timeout information:
--- Timeout information end.
elapsed time (seconds): 498.791
----------configuration:(9/1111)----------
Boot Layer
  class path: /scratch/opt/mach5/mesos/work_dir/jib-master/install/jtreg/5.0/b01/bundles/jtreg_bin-5.0.zip/jtreg/lib/javatest.jar
              /scratch/opt/mach5/mesos/work_dir/jib-master/install/jtreg/5.0/b01/bundles/jtreg_bin-5.0.zip/jtreg/lib/jtreg.jar
  patch: java.base /scratch/opt/mach5/mesos/work_dir/slaves/805146e6-8fdb-4552-bf9e-385b73cf7129-S17254/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/e52a132c-fa5a-4e67-899d-b7bfee819424/runs/6167bb40-acf4-4e8d-850a-d1d249a0f644/testoutput/test-support/jtreg_open_test_jdk_tier2_part1/patches/java.base

Test Layer
  class path: /scratch/opt/mach5/mesos/work_dir/slaves/805146e6-8fdb-4552-bf9e-385b73cf7129-S17254/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/e52a132c-fa5a-4e67-899d-b7bfee819424/runs/6167bb40-acf4-4e8d-850a-d1d249a0f644/testoutput/test-support/jtreg_open_test_jdk_tier2_part1/classes/2/sun/security/provider/SecureRandom/StrongSecureRandom.d
              /scratch/opt/mach5/mesos/work_dir/jib-master/install/jdk-15+27-1352/src.full/open/test/jdk/sun/security/provider/SecureRandom

----------rerun:(29/4421)*----------