Revert "[test_runner] Use relative paths in commands."

This reverts commit 1b4a566.

Reason for revert: breaks Fuchsia builders

Original change's description:
> [test_runner] Use relative paths in commands.
>
> This makes it easier to copy commands between checkouts or between the bot and local development.
>
> Change-Id: I74bc9dcb83855e295fe40fa4ef81871ccc537d29
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/400180
> Reviewed-by: Alexander Aprelev <[email protected]>
> Commit-Queue: Ryan Macnak <[email protected]>

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I8c7cca1e9c82a5b6e237d0b7611647a6168e6397
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/437123
Reviewed-by: Siva Annamalai <[email protected]>
Auto-Submit: Ryan Macnak <[email protected]>
Bot-Commit: Rubber Stamper <[email protected]>
Commit-Queue: Ryan Macnak <[email protected]>

Author: rmacnak-google

pkg/test_runner/lib/src/compiler_configuration.dart

@@ -1428,7 +1428,8 @@ abstract mixin class VMKernelCompilerMixin {
 
   Command computeCompileToKernelCommand(String tempDir, List<String> arguments,
       Map<String, String> environmentOverrides) {
-    var genKernel = 'pkg/vm/tool/gen_kernel$shellScriptExtension';
+    var pkgVmDir = Platform.script.resolve('../../../pkg/vm').toFilePath();
+    var genKernel = '$pkgVmDir/tool/gen_kernel$shellScriptExtension';
 
     var kernelBinariesFolder = _configuration.buildDirectory;
     if (_useSdk) {

pkg/test_runner/lib/src/test_suite.dart

@@ -226,6 +226,7 @@ abstract class TestSuite {
 
     TestUtils.mkdirRecursive(Path('.'), generatedTestPath);
     return File(generatedTestPath.toNativePath())
+        .absolute
         .path
         .replaceAll('\\', '/');
   }
@@ -343,7 +344,7 @@ class VMTestSuite extends TestSuite {
             configuration.architecture == Architecture.x64c
         ? '$buildDir/gen/kernel-service.dart.snapshot'
         : '$buildDir/gen/kernel_service.dill';
-    var dfePath = Path(filename).toNativePath();
+    var dfePath = Path(filename).absolute.toNativePath();
     final experiments = [...configuration.experiments];
     var args = [
       ...initialTargetArguments,
@@ -954,7 +955,8 @@ class StandardTestSuite extends TestSuite {
         var nameFromModuleRoot = testFile.path.relativeTo(Repository.dir);
         var nameFromModuleRootNoExt =
             "${nameFromModuleRoot.directoryPath}/$nameNoExt";
-        var jsDir = Path(compilationTempDir).toString();
+        var jsDir =
+            Path(compilationTempDir).relativeTo(Repository.dir).toString();
         var nativeNonNullAsserts =
             testFile.ddcOptions.contains('--native-null-assertions');
         var jsInteropNonNullAsserts =
@@ -1030,16 +1032,15 @@ class StandardTestSuite extends TestSuite {
       args.add('--format=json');
     }
 
-    args.add(testFile.path.relativeTo(Repository.dir).toNativePath());
+    args.add(testFile.path.toNativePath());
 
     return args;
   }
 
   String? packagesArgument(String? packages) {
     // If this test is inside a package, we will check if there is a
     // pubspec.yaml file and if so, create a custom package root for it.
-    packages ??=
-        Path(configuration.packages).relativeTo(Repository.dir).toNativePath();
+    packages ??= Path(configuration.packages).toNativePath();
 
     if (packages == 'none') {
       return null;

tests/standalone/io/process_non_ascii_test.dart

@@ -26,14 +26,12 @@ main() {
   var nonAsciiTxtFile = new File('${nonAsciiDir.path}/æøå.txt');
   nonAsciiTxtFile.writeAsStringSync('æøå');
   var script = nonAsciiFile.path;
-  var absolutePackages = Uri.parse(Platform.packageConfig!).toFilePath();
   // Note: we prevent this child process from using Crashpad handler because
   // this introduces an issue with deleting the temporary directory.
   Process.run(
     executable,
     []
       ..addAll(Platform.executableArguments)
-      ..add("--packages=$absolutePackages")
       ..add(script),
     workingDirectory: nonAsciiDir.path,
     environment: {'DART_CRASHPAD_HANDLER': ''},

tests/standalone/io/regress_7679_test.dart

@@ -35,14 +35,12 @@ main() {
 }
 """);
   String executable = new File(Platform.executable).resolveSymbolicLinksSync();
-  String absolutePackages = Uri.parse(Platform.packageConfig!).toFilePath();
   // Note: we prevent this child process from using Crashpad handler because
   // this introduces an issue with deleting the temporary directory.
   Process.run(
     executable,
     []
       ..addAll(Platform.executableArguments)
-      ..add("--packages=$absolutePackages")
       ..add('script.dart'),
     workingDirectory: temp.path,
     environment: {'DART_CRASHPAD_HANDLER': ''},