@JsonIgnore
	public Boolean isThresholdRunCount() {
		return "R".equals(getThreshold());
	}
Get ip address of target hosts. if target hosts 'a.com:1.1.1.1' add ip: '1.1.1.1' if target
hosts ':1.1.1.1' add ip: '1.1.1.1' if target hosts '1.1.1.1' add ip: '1.1.1.1'
if www.test.com:0:0:0:0:0:ffff:3d87:a969 add ip: '0:0:0:0:0:ffff:3d87:a969'

@return host ip list
ngrinder-core/src/main/java/org/ngrinder/model/PerfTest.java