Select most specific overloaded function/property by explicitly used arguments only.

Major rewrite of OverloadingConflictResolver.

compiler/testData/diagnostics/tests/resolve/overloadConflicts/varargsInDifferentPositions.kt

@@ -0,0 +1,12 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+object X1
+object X2
+
+fun overloadedFun(arg: String, vararg args: String) = X1
+fun overloadedFun(arg: String, vararg args: String, flag: Boolean = true) = X2
+
+val test1a: X1 = overloadedFun("", "")
+val test1b: X1 = overloadedFun("", args = "")
+val test1c: X2 = overloadedFun("", "", "", flag = true)
+