test(transformer/nullish-coalescing): failing test (#8051)

Add failing test for nullish coalescing operator. The output is correct, but temp var is created in wrong scope.

My guess is that it needs to use `current_hoist_scope_id`, not `current_scope_id`.

This test from class properties also shows the same problem: https://github.com/oxc-project/oxc/blob/ac097e916051288cc982136e4e22c2766cb4bd91/tasks/transform_conformance/snapshots/oxc.snap.md?plain=1#L20-L35

tasks/transform_conformance/snapshots/oxc.snap.md

@@ -1,11 +1,10 @@
 commit: 54a8389f
 
-Passed: 117/135
+Passed: 117/136
 
 # All Passed:
 * babel-plugin-transform-class-static-block
 * babel-plugin-transform-logical-assignment-operators
-* babel-plugin-transform-nullish-coalescing-operator
 * babel-plugin-transform-optional-catch-binding
 * babel-plugin-transform-async-generator-functions
 * babel-plugin-transform-object-rest-spread
@@ -56,6 +55,19 @@ after transform: SymbolId(0): [ReferenceId(0), ReferenceId(2), ReferenceId(6), R
 rebuilt        : SymbolId(0): [ReferenceId(0), ReferenceId(2), ReferenceId(6), ReferenceId(10)]
 
 
+# babel-plugin-transform-nullish-coalescing-operator (2/3)
+* in-nested-block/input.js
+Bindings mismatch:
+after transform: ScopeId(0): []
+rebuilt        : ScopeId(0): ["_x"]
+Bindings mismatch:
+after transform: ScopeId(1): ["_x"]
+rebuilt        : ScopeId(1): []
+Symbol scope ID mismatch for "_x":
+after transform: SymbolId(0): ScopeId(1)
+rebuilt        : SymbolId(0): ScopeId(0)
+
+
 # babel-plugin-transform-async-to-generator (14/15)
 * super/nested/input.js
 x Output mismatch

tasks/transform_conformance/tests/babel-plugin-transform-nullish-coalescing-operator/test/fixtures/in-nested-block/input.js

@@ -0,0 +1,3 @@
+{
+  x ?? y
+}

tasks/transform_conformance/tests/babel-plugin-transform-nullish-coalescing-operator/test/fixtures/in-nested-block/output.js

@@ -0,0 +1,4 @@
+{
+  var _x;
+  (_x = x) !== null && _x !== void 0 ? _x : y;
+}