Remove leftovers of platformName and platformStatic in test data

Drop unnecessary imports, rename some tests

compiler/testData/diagnostics/testsWithStdLib/duplicateJvmSignature/jvmNames.kt

@@ -0,0 +1,22 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+@JvmName("bar")
+fun foo(a: Any) {}
+
+fun Any.foo() {}
+
+@JvmName("barInt")
+fun bar(x: List<Int>) {}
+
+@JvmName("barStr")
+fun bar(x: List<String>) {}
+
+class C {
+    var rwProp: Int
+        @JvmName("get_rwProp")
+        get() = 0
+        @JvmName("set_rwProp")
+        set(v) {}
+
+    fun getRwProp(): Int = 123
+    fun setRwProp(v: Int) {}
+}