OLMIS-4308, switch to sequential tests with more concurrency per test
Without sequential testing, the JMeter tests without a cluster of test execution machines, was tripping over itself. Hogging large amounts of memory, maxing the CPU, and encountering longer data analysis delays. Reducing the length of each test, running it singularly, but setting a concurrent virtual user number of 30 per test appears to be within the capability of the build servers (far reduced memory usage, and moderate-heavy CPU usage) while still getting similar load to the test target.