Only disable optimizations with coverage.

This means that any test runs without coverage will run optimized
Solidity code instead.

lib/tests/run_tests.js

@@ -39,7 +39,7 @@ function runJSTests(files, options, cb) {
   async.waterfall([
     function setupGlobalNamespace(next) {
       // TODO put default config
-      const test = new Test({loglevel, node: options.node});
+      const test = new Test({loglevel, node: options.node, coverage: options.coverage});
       global.embark = test;
       global.assert = assert;
       global.config = test.config.bind(test);

lib/tests/test.js

@@ -154,7 +154,7 @@ class Test {
     this.engine.startService("deployment", {
       trackContracts: false,
       compileOnceOnly: true,
-      disableOptimizations: true
+      disableOptimizations: this.options.coverage
     });
     this.gasLimit = 6000000;
     this.engine.events.request('deploy:setGasLimit', this.gasLimit);