[FIR TEST]: add problematic test with WeakHashMap.get ambiguity

compiler/fir/resolve/testData/resolve/stdlib/problems/weakHashMap.kt

@@ -0,0 +1,10 @@
+// FULL_JDK
+
+import java.util.*
+
+val someMap = WeakHashMap<Any?, Any?>()
+
+fun foo() {
+    <!AMBIGUITY!>someMap[""]<!>
+}
+

compiler/fir/resolve/testData/resolve/stdlib/problems/weakHashMap.txt

@@ -0,0 +1,6 @@
+FILE: weakHashMap.kt
+    public final val someMap: R|java/util/WeakHashMap<kotlin/Any?, kotlin/Any?>| = R|java/util/WeakHashMap.WeakHashMap|<R|kotlin/Any?|, R|kotlin/Any?|>()
+        public get(): R|java/util/WeakHashMap<kotlin/Any?, kotlin/Any?>|
+    public final fun foo(): R|kotlin/Unit| {
+        R|/someMap|.<Ambiguity: get, [java/util/WeakHashMap.get, kotlin/collections/Map.get]>#(String())
+    }

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirDiagnosticsWithStdlibTestGenerated.java

@@ -591,5 +591,10 @@ public class FirDiagnosticsWithStdlibTestGenerated extends AbstractFirDiagnostic
         public void testTryWithLambdaInside() throws Exception {
             runTest("compiler/fir/resolve/testData/resolve/stdlib/problems/tryWithLambdaInside.kt");
         }
+
+        @TestMetadata("weakHashMap.kt")
+        public void testWeakHashMap() throws Exception {
+            runTest("compiler/fir/resolve/testData/resolve/stdlib/problems/weakHashMap.kt");
+        }
     }
 }