RFR: 8234905: [test] TestElfDirectRead fails on ARM32 due to missing call stack information

[christoph.goettschkes at microdoc.com]

Hi,

please review the following change, which disables a test [1] for ARM32:

http://cr.openjdk.java.net/~cgo/8234905/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8234905

The problematic test uses a VM feature for verification, which is not 
available on ARM32. The memory tracker normally outputs call stack 
information for memory regions. This is not the case for ARM32 in thumb 
mode, because the JVM is not able to retrieve these information [2]. I 
also don't see a way to implement this feature in the VM. The test could 
only be fixed, if a completely different verification mechanism is used.

I don't think it is reasonable to re-write the whole test just for this 
one platform. If required, a new test for this feature could be implement, 
which is only executed on ARM32.

The os.arch property is set to "arm" for 32-bit ARM and to "aarch64" for 
64-bit ARM. The test still executes and succeeds on aarch64.

Thanks,
Christoph

[1]
https://hg.openjdk.java.net/jdk/jdk/file/c6d7bb2146aa/test/hotspot/jtreg/runtime/ElfDecoder/TestElfDirectRead.java
[2]
https://hg.openjdk.java.net/jdk/jdk/file/c6d7bb2146aa/src/hotspot/os_cpu/linux_arm/os_linux_arm.cpp#l227