Move tInputWarning validation to unit tests

[john-science]

This basic Material validation test is happening during runtime, but I believe it should be handled as a unit test:

armi/armi/reactor/components/component.py

Lines 241 to 254 in de18f60

	def tInputWarning(self, Tinput):
	"""
	Check whether thermal expansion factor is 0.0% exactly at T=Tinput
	"""
	expansionFactor = (
	self.material.linearExpansionPercent(Tc=self.inputTemperatureInC) / 100.0
	)
	if not (abs(expansionFactor) < 1.0e-6):
	runLog.warning(
	f"Thermal expansion for {self.material} at Tinput = {Tinput} is non-zero "
	f"({expansionFactor}). The modeled density for this material will be off "
	f"by a factor of {(1 + expansionFactor) ** 2}.",
	single=True,
	)

[mgjarrett]

See #860; it's going to remove this method entirely