all: use T.TempDir to create temporary test directory (#8280)

This commit replaces `os.MkdirTemp` with `t.TempDir` in tests. The
directory created by `t.TempDir` is automatically removed when the test
and all its subtests complete.

Prior to this commit, temporary directory created using `os.MkdirTemp`
needs to be removed manually by calling `os.RemoveAll`, which is omitted
in some tests. The error handling boilerplate e.g.
	defer func() {
		if err := os.RemoveAll(dir); err != nil {
			t.Fatal(err)
		}
	}
is also tedious, but `t.TempDir` handles this for us nicely.

Reference: https://pkg.go.dev/testing#T.TempDir
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

lib/fs/basicfs_windows_test.go

@@ -49,7 +49,6 @@ func TestResolveWindows83(t *testing.T) {
 		dir = fs.resolveWin83(dir)
 		fs = newBasicFilesystem(dir)
 	}
-	defer os.RemoveAll(dir)
 
 	shortAbs, _ := fs.rooted("LFDATA~1")
 	long := "LFDataTool"
@@ -80,7 +79,6 @@ func TestIsWindows83(t *testing.T) {
 		dir = fs.resolveWin83(dir)
 		fs = newBasicFilesystem(dir)
 	}
-	defer os.RemoveAll(dir)
 
 	tempTop, _ := fs.rooted(TempName("baz"))
 	tempBelow, _ := fs.rooted(filepath.Join("foo", "bar", TempName("baz")))