test_infra: Enable cross-build for "musl" and "aarch64" targets

With enabling the `vendered-openssl` feature, we can now cross-build the
`test_infra` crate for  "musl" and "aarch64" targets. In this way, we
can remove the `test_infra` crate from the "exclude" list, so that this
crate can be checked and processed by "cargo clippy" and "cargo fmt".

More details can be found: https://docs.rs/openssl/latest/openssl/#vendored

As 'musl-gcc' is required, this commit also installs the `musl-tools`
package for our "build" github action on the musl target [1].

[1] https://github.com/actions-rs/toolchain/issues/102

Signed-off-by: Bo Chen <chen.bo@intel.com>

Cargo.lock

@@ -542,6 +542,15 @@ dependencies = [
  "vmm-sys-util",
 ]
 
+[[package]]
+name = "openssl-src"
+version = "111.17.0+1.1.1m"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05d6a336abd10814198f66e2a91ccd7336611f30334119ca8ce300536666fcf4"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "openssl-sys"
 version = "0.9.72"
@@ -551,6 +560,7 @@ dependencies = [
  "autocfg",
  "cc",
  "libc",
+ "openssl-src",
  "pkg-config",
  "vcpkg",
 ]