kola/harness.go: Update the arch detection for kola tests

While running the kola tests on cloud platforms, our
arch processing would pick the architecture of the host
instead of the machine that we were running on. This
caused an error where our tests were running on arch where
they were not supposed to as per their architectures arg
in their test description

mantle/kola/harness.go

@@ -58,7 +58,6 @@ import (
 	"github.com/coreos/coreos-assembler/mantle/platform/machine/qemuiso"
 	"github.com/coreos/coreos-assembler/mantle/system"
 	"github.com/coreos/coreos-assembler/mantle/util"
-	coreosarch "github.com/coreos/stream-metadata-go/arch"
 )
 
 // InstalledTestsDir is a directory where "installed" external
@@ -599,7 +598,7 @@ func filterTests(tests map[string]*register.Test, patterns []string, pltfrm stri
 				isExcluded = true
 				break
 			}
-			allowedArchitecture, _ := isAllowed(coreosarch.CurrentRpmArch(), t.Architectures, t.ExcludeArchitectures)
+			allowedArchitecture, _ := isAllowed(Options.CosaBuildArch, t.Architectures, t.ExcludeArchitectures)
 			allowed = allowed || (allowedPlatform && allowedArchitecture)
 		}
 		if isExcluded || !allowed {
@@ -622,7 +621,7 @@ func filterTests(tests map[string]*register.Test, patterns []string, pltfrm stri
 				delete(t.NativeFuncs, k)
 				continue
 			}
-			_, excluded = isAllowed(coreosarch.CurrentRpmArch(), nil, NativeFuncWrap.Exclusions)
+			_, excluded = isAllowed(Options.CosaBuildArch, nil, NativeFuncWrap.Exclusions)
 			if excluded {
 				delete(t.NativeFuncs, k)
 			}
@@ -717,7 +716,7 @@ func runProvidedTests(testsBank map[string]*register.Test, patterns []string, mu
 	}
 
 	if len(tests) == 0 {
-		plog.Fatalf("There are no matching tests to run on this architecture/platform: %s %s", coreosarch.CurrentRpmArch(), pltfrm)
+		plog.Fatalf("There are no matching tests to run on this architecture/platform: %s %s", Options.CosaBuildArch, pltfrm)
 	}
 
 	tests, err = filterDenylistedTests(tests)
@@ -1216,7 +1215,7 @@ ExecStart=%s
 	// Architectures using 64k pages use slightly more memory, ask for more than requested
 	// to make sure that we don't run out of it. Currently, only ppc64le uses 64k pages by default.
 	// See similar logic in boot-mirror.go and luks.go.
-	switch coreosarch.CurrentRpmArch() {
+	switch Options.CosaBuildArch {
 	case "ppc64le":
 		if targetMeta.MinMemory <= 4096 {
 			targetMeta.MinMemory = targetMeta.MinMemory * 2