Fix uninitialized constant in test.

[wtn]

Running sus test/async/http/client/google.rb results in 1 test error:

describe Async::HTTP::Client it can request remote resource with compression test/async/http/client/google.rb:35
	expect #<Async::HTTP::Protocol::HTTP2::Response:0xa50 status=200> to
		be success?
			✓ assertion passed test/async/http/client/google.rb:40
	⚠ NameError: uninitialized constant Async::HTTP::Body::Inflate
		test/async/http/client/google.rb:42 block (3 levels) in <top (required)>

The other test files are OK.

Contribution

• I tested my changes locally.
• I agree to the Developer's Certificate of Origin 1.1.

[ioquatix]

Thanks!