Report CORINFO_CALLCONV_GENERIC to JIT (#121561)

Outerloops are broken.

Apparently we got away without reporting this until the test in #121130
was added. Not reporting the calling convention results in this not
kicking in:


https://github.com/dotnet/runtime/blob/5e97723bdd8eb9eff95c52b7120cec6bfb5a0a19/src/coreclr/jit/importer.cpp#L7291-L7297

and failing the test.

Cc @dotnet/ilc-contrib

---------

Co-authored-by: Jan Kotas <[email protected]>

Author: MichalStrehovsky

src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs

@@ -882,6 +882,8 @@ private void Get_CORINFO_SIG_INFO(MethodSignature signature, CORINFO_SIG_INFO* s
             if (!signature.IsStatic) sig->callConv |= CorInfoCallConv.CORINFO_CALLCONV_HASTHIS;
             if (signature.IsExplicitThis) sig->callConv |= CorInfoCallConv.CORINFO_CALLCONV_EXPLICITTHIS;
 
+            if (signature.GenericParameterCount != 0) sig->callConv |= CorInfoCallConv.CORINFO_CALLCONV_GENERIC;
+
             TypeDesc returnType = signature.ReturnType;
 
             CorInfoType corInfoRetType = asCorInfoType(signature.ReturnType, &sig->retTypeClass);