Make single-file classes tolerant to having many main()'s

compiler/testData/diagnostics/testsWithStdLib/CallToMainRedeclaredInMultiFile.kt

@@ -0,0 +1,8 @@
+// FILE: a.kt
+fun main(args: Array<String>) {}
+
+// FILE: b.kt
+fun main(args: Array<String>) {}
+
+// FILE: c.kt
+fun foo() { <!OVERLOAD_RESOLUTION_AMBIGUITY!>main<!>(arrayOf("a", "b")) }

compiler/testData/diagnostics/testsWithStdLib/CallToMainRedeclaredInMultiFile.txt

@@ -0,0 +1,5 @@
+package
+
+public fun foo(): kotlin.Unit
+public fun main(/*0*/ args: kotlin.Array<kotlin.String>): kotlin.Unit
+public fun main(/*0*/ args: kotlin.Array<kotlin.String>): kotlin.Unit

compiler/testData/diagnostics/testsWithStdLib/RedeclarationMainInMultiFileClass.kt

@@ -0,0 +1,11 @@
+// FILE: a.kt
+@file:JvmName("Util")
+@file:JvmMultifileClass
+
+<!CONFLICTING_JVM_DECLARATIONS!>fun main(args: Array<String>)<!> {}
+
+// FILE: b.kt
+@file:JvmName("Util")
+@file:JvmMultifileClass
+
+<!CONFLICTING_JVM_DECLARATIONS!>fun main(args: Array<String>)<!> {}

compiler/testData/diagnostics/testsWithStdLib/RedeclarationMainInMultiFileClass.txt

@@ -0,0 +1,4 @@
+package
+
+public fun main(/*0*/ args: kotlin.Array<kotlin.String>): kotlin.Unit
+public fun main(/*0*/ args: kotlin.Array<kotlin.String>): kotlin.Unit