Improved parsing of internal compiler arguments with boolean state in

case when the argument is listed twice in the list of command line
arguments. The last value will be used.
#KT-27181 Fixed

compiler/testData/cli/jvm/internalArgOverrideOffLanguageFeature.out

@@ -0,0 +1,13 @@
+warning: ATTENTION!
+This build uses unsafe internal compiler arguments:
+
+-XXLanguage;-InlineClasses
+
+This mode is not recommended for production use,
+as no stability/compatibility guarantees are given on
+compiler or generated code. Use it at your own risk!
+
+compiler/testData/cli/jvm/inlineClass.kt:1:1: error: the feature "inline classes" is disabled
+inline class Foo(val x: Int)
+^
+COMPILATION_ERROR