fix(semantic): allow var and function with same name in static blocks (#18358)

## Summary

- Static blocks are var-hoisting boundaries (like functions), so `var x; function x() {}` should be allowed within them
- Added `is_class_static_block()` check to `check_function_redeclaration` to allow this coexistence

Fixes the Babel conformance test: `es2022/class-static-block/duplicate-function-var-name`

## Test plan

- [x] `cargo coverage -- parser` passes
- [x] The test case now parses without error

🤖 Generated with [Claude Code](https://claude.com/claude-code)

crates/oxc_semantic/src/checker/javascript.rs

@@ -686,6 +686,7 @@ pub fn check_function_redeclaration(func: &Function, ctx: &SemanticBuilder<'_>)
     let current_scope_flags = ctx.current_scope_flags();
     if prev.flags.intersects(SymbolFlags::FunctionScopedVariable | SymbolFlags::Function)
         && (current_scope_flags.is_function()
+            || current_scope_flags.is_class_static_block()
             || (!ctx.source_type.is_module() && current_scope_flags.is_top()))
     {
         // https://tc39.github.io/ecma262/#sec-scripts-static-semantics-lexicallydeclarednames

tasks/coverage/snapshots/parser_babel.snap

@@ -2,7 +2,7 @@ commit: fc58af40
 
 parser_babel Summary:
 AST Parsed     : 2221/2227 (99.73%)
-Positive Passed: 2206/2227 (99.06%)
+Positive Passed: 2207/2227 (99.10%)
 Negative Passed: 1649/1689 (97.63%)
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2026/explicit-resource-management/invalid-for-using-of-no-initializer/input.js
 
@@ -84,20 +84,6 @@ Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/ty
 
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/types/invalid-import-type-options-with-spread-element/input.ts
 
-Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2022/class-static-block/duplicate-function-var-name/input.js
-
-  × Identifier `x` has already been declared
-   ╭─[babel/packages/babel-parser/test/fixtures/es2022/class-static-block/duplicate-function-var-name/input.js:3:11]
- 2 │     static {
- 3 │       var x;
-   ·           ┬
-   ·           ╰── `x` has already been declared here
- 4 │       function x() {}
-   ·                ┬
-   ·                ╰── It can not be redeclared here
- 5 │     }
-   ╰────
-
 Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2022/top-level-await-unambiguous/module/input.js
 
   × `await` is only allowed within async functions and at the top levels of modules

tasks/coverage/snapshots/semantic_babel.snap

@@ -2,7 +2,7 @@ commit: fc58af40
 
 semantic_babel Summary:
 AST Parsed     : 2227/2227 (100.00%)
-Positive Passed: 1940/2227 (87.11%)
+Positive Passed: 1941/2227 (87.16%)
 semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/comments/decorators/decorators-after-export/input.js
 Symbol span mismatch for "C":
 after transform: SymbolId(0): Span { start: 65, end: 66 }
@@ -76,9 +76,6 @@ Symbol scope ID mismatch for "_await":
 after transform: SymbolId(3): ScopeId(2)
 rebuilt        : SymbolId(2): ScopeId(0)
 
-semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2022/class-static-block/duplicate-function-var-name/input.js
-Identifier `x` has already been declared
-
 semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2022/top-level-await-unambiguous/module/input.js
 `await` is only allowed within async functions and at the top levels of modules