.github/workflows: tests time out on Linux

[hajimehoshi]

Especially, TestSetBufferSize times out...

https://github.com/ebitengine/oto/actions/runs/14019826523/job/39250274827

=== RUN   TestSetBufferSize
panic: test timed out after 10m0s
	running tests:
		TestSetBufferSize (10m0s)

goroutine 18 [running]:
testing.(*M).startAlarm.func1()
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:2373 +0x385
created by time.goFunc
	/opt/hostedtoolcache/go/1.23.7/x64/src/time/sleep.go:215 +0x2d

goroutine 1 [chan receive]:
testing.(*T).Run(0xc0001084e0, {0x5694bc?, 0x0?}, 0x573490)
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:1751 +0x3ab
testing.runTests.func1(0xc0001084e0)
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:2168 +0x37
testing.tRunner(0xc0001084e0, 0xc000063c08)
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:1690 +0xf4
testing.runTests(0xc0000121c8, {0x66d440, 0x2, 0x2}, {0x2?, 0x10?, 0x688be0?})
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:2166 +0x43d
testing.(*M).Run(0xc00010c0a0)
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:2034 +0x64a
github.com/ebitengine/oto/v3_test.TestMain(0xc00010c0a0)
	/home/runner/work/oto/oto/oto_test.go:39 +0x92
main.main()
	_testmain.go:51 +0xa8

goroutine 6 [sync.Cond.Wait]:
sync.runtime_notifyListWait(0xc000078990, 0x1)
	/opt/hostedtoolcache/go/1.23.7/x64/src/runtime/sema.go:587 +0x159
sync.(*Cond).Wait(0xc00005ee58?)
	/opt/hostedtoolcache/go/1.23.7/x64/src/sync/cond.go:71 +0x85
github.com/ebitengine/oto/v3/internal/mux.(*Mux).wait(0xc00007a6f0)
	/home/runner/work/oto/oto/internal/mux/mux.go:86 +0x95
github.com/ebitengine/oto/v3/internal/mux.(*Mux).loop(0xc00007a6f0)
	/home/runner/work/oto/oto/internal/mux/mux.go:93 +0x56
created by github.com/ebitengine/oto/v3/internal/mux.New in goroutine 1
	/home/runner/work/oto/oto/internal/mux/mux.go:68 +0xf8

goroutine 8 [sleep]:
time.Sleep(0xf4240)
	/opt/hostedtoolcache/go/1.23.7/x64/src/runtime/time.go:[30](https://github.com/ebitengine/oto/actions/runs/14019826523/job/39250274827#step:9:31)0 +0xf2
github.com/ebitengine/oto/v3_test.TestSetBufferSize(0xc000108680?)
	/home/runner/work/oto/oto/oto_test.go:59 +0xeb
testing.tRunner(0xc000108680, 0x573490)
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:1690 +0xf4
created by testing.(*T).Run in goroutine 1
	/opt/hostedtoolcache/go/1.23.7/x64/src/testing/testing.go:1743 +0x390
FAIL	github.com/ebitengine/oto/v3	600.078s
FAIL

[hajimehoshi]

I failed to reproduce this on my Linux desktop, so skip the tests on the CI, not (*testing.T).Skip.