refactor(project): Add internal flag to skip writing resources to dist

By setting UI5_BUILD_NO_WRITE_DEST to any truthy value, build results
will not be written to the dist directory.

This is useful for testing the build performance, focusing on the build
itself rather then the heavy I/O operation of writing the result to
disk.

Author: RandomByte

packages/project/lib/build/ProjectBuilder.js

@@ -251,8 +251,8 @@ class ProjectBuilder {
 					await projectBuildContext.getTaskRunner().runTasks();
 					this.#log.endProjectBuild(projectName, projectType);
 				}
-				if (!requestedProjects.includes(projectName)) {
-					// Project has not been requested
+				if (!requestedProjects.includes(projectName) || !!process.env.UI5_BUILD_NO_WRITE_DEST) {
+					// Project has not been requested or writing is disabled
 					//	=> Its resources shall not be part of the build result
 					continue;
 				}