[Xamarin.Android.Tools.Bytecode] Ignore synthetic ctor params

[jonpryor]

Fixes: #1090

Attempting to parse TensorFlow 1.13.1 with a Debug build of class-parse results in an assertion failure:

% curl -o tensorflow-android-1.13.1.aar https://repo1.maven.org/maven2/org/tensorflow/tensorflow-android/1.13.1/tensorflow-android-1.13.1.aar
% unzip tensorflow-android-1.13.1.aar classes.jar
% dotnet bin/Debug-net7.0/class-parse.dll classes.jar
Unexpected number of method parameters; expected 0, got 1
   at Xamarin.Android.Tools.Bytecode.MethodInfo.UpdateParametersFromMethodParametersAttribute(ParameterInfo[] parameters)
   at Xamarin.Android.Tools.Bytecode.MethodInfo.GetParameters()
   at Xamarin.Android.Tools.Bytecode.XmlClassDeclarationBuilder.GetMethodParameters(MethodInfo method)+MoveNext()
   at System.Xml.Linq.XContainer.AddContentSkipNotify(Object content)
   at System.Xml.Linq.XContainer.AddContentSkipNotify(Object content)
   at Xamarin.Android.Tools.Bytecode.XmlClassDeclarationBuilder.GetMethod(String element, String name, MethodInfo method, String returns)
   at Xamarin.Android.Tools.Bytecode.XmlClassDeclarationBuilder.<GetConstructors>b__23_2(MethodInfo c)

Note: this will only happen for Debug builds of class-parse, which we do not ship. Thus, this will only happen if you are using a local build of xamarin/Java.Interop.

The assertion occurs when processing the constructor for org/tensorflow/Session$Runner$Reference.class, which is a non-static inner class:

% unzip classes.jar 'org/tensorflow/Session$Runner$Reference.class'
% dotnet bin/Debug-net7.0/class-parse.dll --dump 'org/tensorflow/Session$Runner$Reference.class'
…
Methods Count: 2
	0: <init> (Lorg/tensorflow/Session$Runner;)V Public
		Code(60, Unknown[LineNumberTable](30), LocalVariableTableAttribute(LocalVariableTableEntry(Name='this', Descriptor='Lorg/tensorflow/Session$Runner$Reference;', StartPC=0, Index=0)), Xamarin.Android.Tools.Bytecode.StackMapTableAttribute)
		MethodParametersAttribute(MethodParameterInfo(Name='this$1', AccessFlags=Final, Synthetic))

Note the MethodParameterInfo.AccessFlags value for the parameter: AccessFlags=Final, Synthetic. This differs from the Final, Mandated value that is checked for by
MethodInfo.UpdateParametersFromMethodParametersAttribute():

var OuterThis = MethodParameterAccessFlags.Final | MethodParameterAccessFlags.Mandated;
// …
while (startIndex < pinfo.Count &&
    (pinfo [startIndex].AccessFlags & OuterThis) == OuterThis) {
  startIndex++;
}

Because the parameter is Final, Synthetic and not Final, Mandated, the parameter is not skipped, which results in the assertion message expected 0, got 1.

@jonpryor does not know how or why Final, Synthetic is being used by Session$Runner$Reference.class, and is unable to reproduce this particular Java bytecode output with the JDK 1.8 and JDK 11 compilers.

Update MethodInfo.UpdateParametersFromMethodParametersAttribute() to also skip Final, Synthetic parameters. This allows Session$Runner$Reference.class to be processed without assertions:

% dotnet bin/Debug-net7.0/class-parse.dll classes.jar
# no errors

Additionally, update the assertion message so that it includes the declaring class name, method name, and method descriptor.