Use add/set_macros/symbols in ManagedWriter

[jobarr-amzn]

Description of changes:
Rather than rendering an encoding context directive the managed writer now uses set_symbols, set_macros, add_symbols, or add_macros as appropriate. Symbols and macros are not set until the user defines a symbol or macro- until that point system symbols and macros are still more succinctly expressible.

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[popematt]

It would be nice if we could have it write it like this instead, but we can leave that for another day.

(:set_symbols "foo" "bar" "baz")

[jobarr-amzn]

I looked into that briefly- in some cases it is being written that way, so it looks like there's some more thought needed on the tuning or something else I missed.

[tgregg]

In these cases, the $ion:: prefix is not required, right, since the IVM installs the system module? This can be out of scope for this PR, but we might as well refine this at some point to be as succinct as possible.

[jobarr-amzn]

Yes it's the raw writer that is determining this behavior. I'd also like to make this more succinct.

[popematt]

It's the managed writer that needs to determine the behavior because the raw writer should not know whether something is in the macro table or not.

The stepInEExp(SystemMacro) method in the raw writer must always write a system e-expression using the specific text or binary syntax for a system e-exp (which is the current behavior).

To get rid fo the unnecessary $ion prefix, the managed writer need to check whether the desired system macro is in the encoding module. If it is in the encoding module, then the managed writer can use stepInEExp(CharSequence) or stepInEExp(Int, Boolean, Macro), similar to the logic in startMacro (see below). If the system macro is not in the encoding module, then the managed writer needs to call stepInEExp(SystemMacro) (which results in the qualified invocation in text or the EF opcode in binary).

ion-java/src/main/java/com/amazon/ion/impl/bin/IonManagedWriter_1_1.kt

Lines 845 to 853 in 576e018

	private fun startMacro(name: String?, address: Int, definition: Macro) {
	val useNames = options.eExpressionIdentifierStrategy == ManagedWriterOptions_1_1.EExpressionIdentifierStrategy.BY_NAME
	if (useNames && name != null) {
	userData.stepInEExp(name)
	} else {
	val includeLengthPrefix = options.writeLengthPrefix(ContainerType.EEXP, depth + 1)
	userData.stepInEExp(address, includeLengthPrefix, definition)
	}
	}