[Native][Tests] Always use -Xllvm-variant=dev

FileCheck tests force using dev LLVM distribution. It breaks
invocation of LLVM Clang which tries to look for executable in a wrong
directory. Let's keep things simple and always pass dev variant to our
tests.

native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/ObjCToKotlinSteppingInLLDBTest.kt

@@ -18,7 +18,6 @@ import org.jetbrains.kotlin.konan.test.blackbox.support.runner.TestRunChecks
 import org.jetbrains.kotlin.konan.test.blackbox.support.settings.LLDB
 import org.jetbrains.kotlin.konan.test.blackbox.support.settings.PipelineType
 import org.jetbrains.kotlin.konan.test.blackbox.support.settings.Timeouts
-import org.jetbrains.kotlin.konan.test.blackbox.support.settings.configurables
 import org.jetbrains.kotlin.konan.test.blackbox.support.util.ClangDistribution
 import org.jetbrains.kotlin.konan.test.blackbox.support.util.LLDBSessionSpec
 import org.jetbrains.kotlin.konan.test.blackbox.support.util.compileWithClang

native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/compilation/TestCompilation.kt

@@ -66,6 +66,9 @@ internal abstract class BasicCompilation<A : TestCompilationArtifact>(
         add(
             "-Xverify-ir=error"
         )
+        // We use dev distribution for tests as it provides a full set of testing utilities,
+        // which might not be available in user distribution.
+        add("-Xllvm-variant=dev")
         addFlattened(binaryOptions.entries) { (name, value) -> listOf("-Xbinary=$name=$value") }
     }
 
@@ -476,7 +479,6 @@ internal class ExecutableCompilation(
 
         internal fun ArgsBuilder.applyFileCheckArgs(fileCheckStage: String?, fileCheckDump: File?) =
             fileCheckStage?.let {
-                add("-Xllvm-variant=dev")  // FileCheck utility is provided in `LLVM dev`, not `LLVM user`
                 add("-Xsave-llvm-ir-after=$it")
                 add("-Xsave-llvm-ir-directory=${fileCheckDump!!.parent}")
             }

native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/util/Clang.kt

@@ -52,16 +52,17 @@ internal fun AbstractNativeSimpleTest.compileWithClang(
         ClangMode.C -> "clang"
         ClangMode.CXX -> "clang++"
     }
+    val configurables = testRunSettings.configurables
     val clangPath = when (clangDistribution) {
-        ClangDistribution.Toolchain -> "${testRunSettings.configurables.absoluteTargetToolchain}/bin/$clangExecutableName"
-        ClangDistribution.Llvm -> "${testRunSettings.configurables.absoluteLlvmHome}/bin/$clangExecutableName"
+        ClangDistribution.Toolchain -> "${configurables.absoluteTargetToolchain}/bin/$clangExecutableName"
+        ClangDistribution.Llvm -> "${configurables.absoluteLlvmHome}/bin/$clangExecutableName"
     }
     val process = ProcessBuilder(
         clangPath,
         *sourceFiles.map { it.absolutePath }.toTypedArray(),
         *includeDirectories.flatMap { listOf("-I", it.absolutePath) }.toTypedArray(),
-        "-isysroot", testRunSettings.configurables.absoluteTargetSysRoot,
-        "-target", testRunSettings.configurables.targetTriple.toString(),
+        "-isysroot", configurables.absoluteTargetSysRoot,
+        "-target", configurables.targetTriple.toString(),
         "-g", "-fmodules",
         *frameworkDirectories.flatMap { listOf("-F", it.absolutePath) }.toTypedArray(),
         *libraryDirectories.flatMap { listOf("-L", it.absolutePath) }.toTypedArray(),