Added tests for --no-append-metadata

- Command line tests
- Documented the standard json
- Changelog
- A Change in SolidityExecutionFramework to prevent flaky gas tests
- A boost test for --no-append-metadata
- Removed an outdated comment

test/libsolidity/GasCosts.cpp

@@ -92,6 +92,7 @@ BOOST_AUTO_TEST_CASE(string_storage)
 		}
 	)";
 	m_compiler.setMetadataFormat(CompilerStack::MetadataFormat::NoMetadata);
+	m_appendCBORMetadata = false;
 	compileAndRun(sourceCode);
 
 	auto evmVersion = solidity::test::CommonOptions::get().evmVersion();