`PerformanceHarness` version roll back ambiguity

[spoonincode]

PerformanceHarness configures itself differently based on what nodeos --full-version returns. Its behavior is altered if the version begins with v2 or v4 with the assumption if it's not one of those versions it must be the "latest". So for spring v1 this code still does what is expected ("latest"), but spring v2 will not follow the expected path. Examples,

spring/tests/PerformanceHarness/performance_test_basic.py

Lines 128 to 131 in bef48a2

	if "v2" in self.nodeosVers:
	validationNodeSpecificNodeosStr += '--plugin eosio::history_api_plugin --filter-on "*" '
	else:
	#If prodsEnableTraceApi, then Cluster configures all nodes with trace_api_plugin so no need to duplicate here

spring/tests/PerformanceHarness/performance_test_basic.py

Lines 144 to 147 in bef48a2

	if "v4" in self.nodeosVers:
	apiNodeSpecificNodeosStr += f"--read-only-threads {self.apiNodesReadOnlyThreadCount} "
	if apiNodeSpecificNodeosStr:
	self.specificExtraNodeosArgs.update({f"{nodeId}" : apiNodeSpecificNodeosStr for nodeId in self._apiNodeIds})

[bhazzard]

For now let's remove this code handling of versions.

We only care about performance relative to the previous major version. One way to do that is to run the performance harness independently on each major version. If the new performance harness has changes to tests / metrics that aren't backported, that approach won't work. In that case we may need to reintroduce only for the previous supported version.

Similar issue: #48