[Bug]: UnsupportedSpecializationException with MappingProxyType

首先复现 issue 中的最小 MappingProxyType 代码片段，然后检查堆栈跟踪中由 MappingproxyBuiltinsFactory.GetNodeFactory 标识的 mappingproxy 实现。确认该调用不再引发 UnsupportedSpecializationException，并添加一个覆盖该代码片段的回归测试。

Describe the bug

GraalPy crashes when running this fuzzed code:

from types import MappingProxyType
MappingProxyType.get(None, None)

Operating system

Linux

CPU architecture

x86_64

GraalPy version

GraalPy 3.13.14 (Oracle GraalVM Native 25.3.4.1)

JDK version

No response

Context configuration

No response

Steps to reproduce

Snippet listed above

Expected behavior

No crash

Stack trace

Unexpected values provided for MappingproxyBuiltinsFactory.GetNodeFactory.GetNodeGen@143c64bb: [None, None, NoValue], [PNone,PNone,PNone]
com.oracle.truffle.api.dsl.UnsupportedSpecializationException: Unexpected values provided for MappingproxyBuiltinsFactory.GetNodeFactory.GetNodeGen@143c64bb: [None, None, NoValue], [PNone,PNone,PNone]
	at org.graalvm.py/com.oracle.graal.python.builtins.objects.mappingproxy.MappingproxyBuiltinsFactory$GetNodeFactory$GetNodeGen.executeAndSpecialize(MappingproxyBuiltinsFactory.java:1061)
	at org.graalvm.py/com.oracle.graal.python.builtins.objects.mappingproxy.MappingproxyBuiltinsFactory$GetNodeFactory$GetNodeGen.execute(MappingproxyBuiltinsFactory.java:1032)
	at org.graalvm.py/com.oracle.graal.python.nodes.function.builtins.BuiltinCallNode$BuiltinAnyCallNode.execute(BuiltinCallNode.java:64)
	at org.graalvm.py/com.oracle.graal.python.nodes.function.BuiltinFunctionRootNode.execute(BuiltinFunctionRootNode.java:337)
	at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:808)
	at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:722)
	at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:641)
	at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
	at com.oracle.truffle.enterprise.svm/com.oracle.svm.enterprise.truffle.compiler.SubstrateEnterpriseOptimizedCallTarget.invokeCompiledAdapterOrCallBoundary(SubstrateEnterpriseOptimizedCallTarget.java:293)
	at com.oracle.truffle.enterprise.svm/com.oracle.svm.enterprise.truffle.compiler.SubstrateEnterpriseOptimizedCallTarget.invokeFromInterpreter(SubstrateEnterpriseOptimizedCallTarget.java:269)
	at com.oracle.truffle.enterprise.svm/com.oracle.svm.enterprise.truffle.compiler.SubstrateEnterpriseOptimizedCallTarget.doInvoke(SubstrateEnterpriseOptimizedCallTarget.java:255)
	at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:573)
	at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.call(OptimizedCallTarget.java:519)
	at org.graalvm.truffle/com.oracle.truffle.api.nodes.IndirectCallNode$1.call(IndirectCallNode.java:96)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.CallDispatchers$SimpleIndirectInvokeNode.doIndirect(CallDispatchers.java:167)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.CallDispatchersFactory$SimpleIndirectInvokeNodeGen$Uncached.execute(CallDispatchersFactory.java:307)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.CallDispatchers$BuiltinFunctionCachedCallNode.callBuiltinFunctionMegamorphic(CallDispatchers.java:265)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.CallDispatchersFactory$BuiltinFunctionCachedCallNodeGen$Uncached.execute(CallDispatchersFactory.java:1173)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.CallNode.builtinFunctionCall(CallNode.java:152)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.CallNodeGen$Uncached.executeInternal(CallNodeGen.java:619)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.CallNode.execute(CallNode.java:128)
	at org.graalvm.py/com.oracle.graal.python.nodes.call.special.CallTernaryMethodNode.call(CallTernaryMethodNode.java:176)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode_dsl.PBytecodeDSLRootNodeGen$CallTernaryMethod_Node.execute$uncached(PBytecodeDSLRootNodeGen.java)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode_dsl.PBytecodeDSLRootNodeGen$UncachedBytecodeNodeTailCall.handleCallTernaryMethod_(PBytecodeDSLRootNodeGen.java:37882)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode_dsl.PBytecodeDSLRootNodeGen$UncachedBytecodeNodeTailCall.__stub_handleCallTernaryMethod_(PBytecodeDSLRootNodeGen.java:0)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode_dsl.PBytecodeDSLRootNodeGen$UncachedBytecodeNodeTailCall.continueAt(PBytecodeDSLRootNodeGen.java:35093)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode_dsl.PBytecodeDSLRootNodeGen.continueAt(PBytecodeDSLRootNodeGen.java:3501)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode_dsl.PBytecodeDSLRootNodeGen.execute(PBytecodeDSLRootNodeGen.java:3493)
[...snip...]

Additional context

No response