Content of splitted modules differ each build

[devtomtom]

Expected Behavior

When splitting modules in different parts by setting the numberOfParts property in the ui5.yaml, it is expected that the resulting modules are always the same.

Current Behavior

The resulting parts differ each time when building the project depending on the file sizes.

Steps to reproduce the issue

1. clone the project ui5-builder
2. adapt libraryHTree in test/lib/builder/builder.js to

const libraryHTree = {
	"id": "library.h",
	"version": "1.0.0",
	"path": libraryHPath,
	"dependencies": [],
	"_level": 0,
	"specVersion": "0.1",
	"type": "library",
	"metadata": {
		"name": "library.h",
		"copyright": "Some fancy copyright"
	},
	"resources": {
		"configuration": {
			"paths": {
				"src": "main/src",
				"test": "main/test"
			}
		},
		"pathMappings": {
			"/resources/": "main/src",
			"/test-resources/": "main/test"
		}
	},
	"builder": {
		"bundles": [{
			"bundleDefinition": {
				"name": "library/h/customBundle.js",
				"defaultFileTypes": [".js"],
				"sections": [{
					"mode": "preload",
					"filters": [
						"library/h/some.js",
						"library/h/library.js",
						"library/h/file.js",
						"!library/h/not.js"
					],
					"resolve": false,
					"renderer": false
				}]
			},
			"bundleOptions": {
				"optimize": true,
				"usePredefinedCalls": true,
                                 "numberOfParts": 4
			}
		}],
		"componentPreload": [
			"components",
			"components/subcomponent1",
			"components/subcomponent2",
			"components/subcomponent3",
		]
	}
};

3. run npm run unit-inspect test/lib/builder/builder.js

Context

• OS/Platform: MacOS
• Node.js Version: v.8.10.0
• npm Version: 5.6.0

Affected components

• [x] ui5-builder
• [ ] ui5-server
• [ ] ui5-cli
• [ ] ui5-fs
• [ ] ui5-project
• [ ] ui5-logger