cmd/compile: remove amd64p32 related SSA rules

Updates #30439

Change-Id: Iadc737e4c6bb05bb576fe4bb344ad92403697352
Reviewed-on: https://go-review.googlesource.com/c/go/+/201380
Run-TryBot: Ben Shi <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Keith Randall <[email protected]>

Author: benshi001

src/cmd/compile/internal/ssa/gen/AMD64.rules

@@ -226,9 +226,6 @@
 (NeqPtr x y) && config.PtrSize == 4 -> (SETNE (CMPL x y))
 (Neq(32|64)F x y) -> (SETNEF (UCOMIS(S|D) x y))
 
-(Int64Hi x) -> (SHRQconst [32] x)         // needed for amd64p32
-(Int64Lo x) -> x
-
 // Lowering loads
 (Load <t> ptr mem) && (is64BitInt(t) || isPtr(t) && config.PtrSize == 8) -> (MOVQload ptr mem)
 (Load <t> ptr mem) && (is32BitInt(t) || isPtr(t) && config.PtrSize == 4) -> (MOVLload ptr mem)