KLIB: Fix reading property lists in Properties.propertyList()

1. If property is absent, or contains empty string or a string consisting only of whitespace characters, Properties.propertyList() should always return empty List<String>.
2. If property starts or ends with whitespace characters, Properties.propertyList() should not include empty-string values for whitespace prefix or suffix.

compiler/util-klib/src/org/jetbrains/kotlin/library/KotlinLibrary.kt

@@ -67,7 +67,3 @@ val KotlinLibrary.packageFqName: String?
 
 val KotlinLibrary.exportForwardDeclarations
     get() = manifestProperties.propertyList(KLIB_PROPERTY_EXPORT_FORWARD_DECLARATIONS, escapeInQuotes = true)
-        .asSequence()
-        .map { it.trim() }
-        .filter { it.isNotEmpty() }
-        .toList()