[cosim] adjust uart addr to 0x90000000 to align with soc #1681

Job	Run time
Test elaborate	1m 13s
Build Emulators (v1024-l8-b2)	1m 12s
Build trace emulator (v1024-l8-b2)	1m 12s
Build Emulators (v1024-l8-b2-fp)	1m 13s
Build trace emulator (v1024-l8-b2-fp)	1m 13s
Build Emulators (v4096-l8-b4)	1m 11s
Build trace emulator (v4096-l8-b4)	1m 12s
Build Emulators (v4096-l8-b4-fp)	1m 11s
Build trace emulator (v4096-l8-b4-fp)	1m 10s
Prepare for running testcases	1s
Run testcases	1s
Report CI result	1s
Generate matrix for re-testing failing tests	1s
Generate wave for failing tests	1s
	10m 52s

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