Revert "ci: try installing qemu 7.0 from canonical server backports"

[yamt]

This reverts commit 39a2013.

[yamt]

armhf failure

4: Running ../../.wasm-spec-test/test/core/imports.json
4: =======================
4: Test:     imports.wast:672 imports.144.wasm assert_unlinkable
4: Expected: unknown import
4: Actual:   None

s390x failure (somehow expected)

 	  1 - toywasm-cli-simple-module (SEGFAULT)
	  4 - toywasm-cli-timeout-wasi-threads (SEGFAULT)
	  5 - toywasm-cli-wasm3-spec-test-simd (Failed)
	  6 - toywasm-cli-wasm3-spec-test-extended-const (Failed)
	  7 - toywasm-cli-wasm3-spec-test-exception-handling (Failed)
	  8 - toywasm-cli-wasm3-spec-test-multi-memory (Failed)
	  9 - toywasm-cli-wasm3-spec-test-tailcall (Failed)
	 10 - toywasm-cli-wasm3-spec-test-threads (Failed)
	 11 - toywasm-cli-exception-handling-test (Failed)
	 12 - toywasm-cli-exception-handling-test-disable-jump-table (Failed)
	 13 - toywasm-cli-wasi-testsuite (Failed)
	 14 - toywasm-cli-wasi-testsuite-littlefs (Timeout)
	 15 - toywasm-cli-wasmtime-wasi-tests (Failed)
	 16 - toywasm-cli-js-wasm (Failed)
	 17 - toywasm-cli-spidermonkey (Failed)
	 21 - toywasm-cli-littlefs-test (Timeout)
	 22 - toywasm-cli-dyld-test (Failed)
	 23 - toywasm-test (Failed)