Refactor ffi impls into com.oracle.truffle.r.ffi.impl project; add ffi AP; TruffleLLVM all RFFI interfaces implemented; no JNI

Adapted to changes in GR-1767: frame parameter removed from interop functions and transitively from all callers where possible.
Also updated Truffle version in file "suite.py".
Removed class TruffleRFFIFrameHelper since there are no usages any longer.
Removed unnecessary call to CompilerDirectives.transferToInterpreter call in class ValuePrinterNode.

Implemented TruffleRLanguage.toString(RContext context, Object value) and isVisible() to work properly in GraalVM shell and Interop.

mx.fastr: set version dependency to 5.60.0; use mx.get_runtime_jvm_args in preference to mx.classpath

set XZ_HOME package download, fix -m64 regression in GNU R build for Solaris, solaris arch is sparcv9

properly ensure that recommended packages can be built in all situations and are included in the release