[Bug]: java.lang.IndexOutOfBoundsException in PyObjectLookupAttr.readAttributeQuickly

[correctmost]

Describe the bug

GraalPy crashes when running this fuzzed code:

class C:
    pass

C()._

Operating system

Linux

CPU architecture

x86_64

GraalPy version

GraalPy 3.12.8 (Oracle GraalVM Native 25.0.3)

JDK version

No response

Context configuration

No response

Steps to reproduce

Snippet listed above

Expected behavior

No crash

Stack trace

array (length: 1) index (1) is out of bounds!
java.lang.IndexOutOfBoundsException: array (length: 1) index (1) is out of bounds!
	at org.graalvm.truffle/com.oracle.truffle.api.strings.InternalErrors.indexOutOfBounds(InternalErrors.java:56)
	at org.graalvm.truffle/com.oracle.truffle.api.strings.AbstractTruffleString.boundsCheckI(AbstractTruffleString.java:536)
	at org.graalvm.truffle/com.oracle.truffle.api.strings.AbstractTruffleString.boundsCheck(AbstractTruffleString.java:491)
	at org.graalvm.truffle/com.oracle.truffle.api.strings.TruffleString$CodePointAtIndexNode.readCodePoint(TruffleString.java:3612)
	at org.graalvm.truffle/com.oracle.truffle.api.strings.TruffleStringFactory$CodePointAtIndexNodeGen$Uncached.execute(TruffleStringFactory.java:2375)
	at org.graalvm.truffle/com.oracle.truffle.api.strings.TruffleString$CodePointAtIndexNode.execute(TruffleString.java:3560)
	at org.graalvm.py/com.oracle.graal.python.lib.PyObjectLookupAttr.readAttributeQuickly(PyObjectLookupAttr.java:325)
	at org.graalvm.py/com.oracle.graal.python.lib.PyObjectGetAttr.getDynamicAttr(PyObjectGetAttr.java:106)
	at org.graalvm.py/com.oracle.graal.python.lib.PyObjectGetAttrNodeGen$Uncached.execute(PyObjectGetAttrNodeGen.java:469)
	at org.graalvm.py/com.oracle.graal.python.lib.PyObjectGetAttr.executeCached(PyObjectGetAttr.java:77)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode.PBytecodeRootNode.bytecodeLoadAttr(PBytecodeRootNode.java:4894)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode.PBytecodeRootNode.bytecodeLoop(PBytecodeRootNode.java:1911)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode.PBytecodeRootNode.executeUncached(PBytecodeRootNode.java:1262)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode.PBytecodeRootNode.executeFromBci(PBytecodeRootNode.java:1246)
	at org.graalvm.py/com.oracle.graal.python.nodes.bytecode.PBytecodeRootNode.execute(PBytecodeRootNode.java:1092)
[...snip...]

Additional context

No response