Replace raw-register AMO asm with proper inline-asm constraints
for all three operands (rd, rs2, rs1). Use long long for .d-word
AMO variants with pre-set values (xd=0xCAFEBABECAFEBABE,
val=0xDEADBEEFDEADBEEF) to avoid uninitialized-data issues.
Restore csr_pseudo_main printf output and re-enable amo_main()
in the test (was commented out as 'crash on qemu').
Use GEN = $(GEN-TCC) since GCC and TCC produce different fcsr
initial values on riscv64.
Revert 199369bb17
- generating test.ref with tcc makes little sense.
- combine riscv_asm & conversion tests into only two files.
(too many files are bad ...)
