[macOS] Emulation speed and CPU usage benchmarks

So, I've been comparing versions and builds, with various toolchains and Qt versions too. Tests were done on macOS 10.14 on a 6-core i7-8850H with 16 GB of RAM... results are odd.

I'm running releases builds with the following settings: unthrottled speed, no frame-skipping, 2 docks only (LCD and settings) at minimum window size (ROM: 83PCE 5.3.1 / 5.3.1.) For emulation speed % and wait a few seconds to average the value after the calculator has finished booting (home screen, blinking cursor).

Note: I'm writing "v1.2-dev" as 6c7b5e0 right now, which is the current master.

CEmu	Qt	Toolchain / SDK	Emul. speed %		CPU usage %
			No SPI	SPI	No SPI	SPI	SPI, throttled 100%
v1.1.1	5.11.1	10.13 X9	5200	1100	109	111	33
		10.14 X10	1700	900	188	196	86
	5.12.0	10.13 X9	4800	1000	110	113	41
		10.14 X10	2800	900	194	198	72
v1.2-dev	5.11.1	10.13 X9	5000	1000	109	111	41
		10.14 X10	1800	900	189	198	75
	5.12.0	10.13 X9	5000	1000	109	110	37
		10.14 X9	5000	1000	105	107	34
		10.14 X10	2500	900	199	194	74
v1.2-dev de46d93	5.12.2	10.13 X10.2	5000	1000	106	108	34

What the hell happened with the 10.14 SDK... ?

Note that I can still repro the slowness issues on XCode 10.2, 10.14 toolchain, and Qt 5.12.2. But good with XCode 10.2, 10.13 toolchain, and Qt 5.12.2.