Remove unused references to SafeHandle methods in corelib.h (#121681)

The uses of these were removed in #100267.

Author: AustinWise

src/coreclr/vm/corelib.h

@@ -881,10 +881,6 @@ DEFINE_CLASS(CALLCONV_SWIFT,                 CompilerServices,       CallConvSwi
 
 DEFINE_CLASS(SAFE_HANDLE,         Interop,                SafeHandle)
 DEFINE_FIELD(SAFE_HANDLE,           HANDLE,                 handle)
-DEFINE_METHOD(SAFE_HANDLE,          GET_IS_INVALID,         get_IsInvalid,              IM_RetBool)
-DEFINE_METHOD(SAFE_HANDLE,          RELEASE_HANDLE,         ReleaseHandle,              IM_RetBool)
-DEFINE_METHOD(SAFE_HANDLE,          DISPOSE,                Dispose,                    IM_RetVoid)
-DEFINE_METHOD(SAFE_HANDLE,          DISPOSE_BOOL,           Dispose,                    IM_Bool_RetVoid)
 
 DEFINE_CLASS(SECURITY_EXCEPTION,    Security,               SecurityException)
 

src/coreclr/vm/metasig.h

@@ -502,7 +502,6 @@ DEFINE_METASIG_T(SM(IntPtr_RuntimeType_RetDelegate, I C(CLASS), C(DELEGATE)))
 
 DEFINE_METASIG(IM(RetRefByte, _, r(b)))
 DEFINE_METASIG_T(IM(Type_RetArrObj, C(TYPE) F, a(j)))
-DEFINE_METASIG(IM(Bool_RetVoid, F, v))
 DEFINE_METASIG_T(IM(BindingFlags_RetArrFieldInfo, g(BINDING_FLAGS), a(C(FIELD_INFO))))
 DEFINE_METASIG_T(IM(BindingFlags_RetArrMethodInfo, g(BINDING_FLAGS), a(C(METHOD_INFO))))
 DEFINE_METASIG_T(IM(BindingFlags_RetArrPropertyInfo, g(BINDING_FLAGS), a(C(PROPERTY_INFO))))

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/SafeHandle.cs

@@ -21,13 +21,6 @@ public abstract partial class SafeHandle : CriticalFinalizerObject, IDisposable
         private static long s_safeHandlesFinalized;
 #endif
 
-        // IMPORTANT:
-        // - Do not add or rearrange fields as the EE depends on this layout,
-        //   as well as on the values of the StateBits flags.
-        // - The EE may also perform the same operations using equivalent native
-        //   code, so this managed code must not assume it is the only code
-        //   manipulating _state.
-
 #if DEBUG && CORECLR
         private readonly string? _ctorStackTrace;
 #endif