based on some finding in https://bugs.openjdk.org/browse/JDK-8351851

There appears to be some ambiguity in what os.arch returns for x86_64 and amd64

For some the expectation is that
/* @test
 * @summary Testing NVRAM mapped byte buffer support
 * @run main/manual PmemTest
 * @requires (os.family == "linux")
 * @requires (os.arch == "x86_64")
 */

should execute on both amd64 and x86_64

This is to perform a deep dive into jtreg's "perception" of the values for os.arch on different platforms

c.f .
open/test/jdk/jdk/internal/util/ArchTest.java
open/src/java.base/share/classes/jdk/internal/util/Architecture.java
./open/make/modules/java.base/gensrc/GensrcMisc.gmk
./build/macosx-aarch64/support/gensrc/java.base/jdk/internal/util/PlatformProps.java