Refactoring: Use unless over if for negative conditions for aws_lc?.

See <https://github.com/rubocop/ruby-style-guide?tab=readme-ov-file#if-vs-unless>.

Author: junaruga

test/openssl/test_bn.rb

@@ -366,7 +366,7 @@ def test_ractor
       assert_equal(true, Ractor.new(@e2) { _1.negative? }.take)
       assert_include(128..255, Ractor.new { OpenSSL::BN.rand(8)}.take)
       assert_include(0...2**32, Ractor.new { OpenSSL::BN.generate_prime(32) }.take)
-      if !aws_lc? # AWS-LC does not support BN::CONSTTIME.
+      unless aws_lc? # AWS-LC does not support BN::CONSTTIME.
         assert_equal(0, Ractor.new { OpenSSL::BN.new(999).get_flags(OpenSSL::BN::CONSTTIME) }.take)
       end
       # test if shareable when frozen

test/openssl/test_pkey_dh.rb

@@ -19,7 +19,7 @@ def test_new_generate
   end if ENV["OSSL_TEST_ALL"]
 
   def test_new_break_on_non_fips
-    omit_on_fips if !aws_lc?
+    omit_on_fips unless aws_lc?
 
     assert_nil(OpenSSL::PKey::DH.new(NEW_KEYLEN) { break })
     assert_raise(RuntimeError) do

test/openssl/test_ssl.rb

@@ -1747,7 +1747,7 @@ def test_get_ephemeral_key
       end
     end
 
-    if !aws_lc? # AWS-LC does not support DHE ciphersuites.
+    unless aws_lc? # AWS-LC does not support DHE ciphersuites.
       # DHE
       # TODO: SSL_CTX_set1_groups() is required for testing this with TLS 1.3
       ctx_proc2 = proc { |ctx|