fix(mir): GPR32/GPR64别名检查移除segments.empty()条件

Wn和Xn是同一硬件寄存器（如W12和X12），GPR32和GPR64 vreg
在同一phys_reg上总是冲突，无论segments是否为空。
原代码要求!segments.empty()，导致某些情况下别名冲突被漏检。

参考: AArch64寄存器别名机制，Wn为Xn的低32位

src/mir/GreedyAlloc.cpp

@@ -482,7 +482,7 @@ bool LiveRegMatrix::CheckInterference(const LiveInterval &li, int phys_reg) cons
         bool gpr32_64_alias =
             (li.reg_class == RegClass::GPR32 && other->reg_class == RegClass::GPR64) ||
             (li.reg_class == RegClass::GPR64 && other->reg_class == RegClass::GPR32);
-        if (gpr32_64_alias && !li.segments.empty() && !other->segments.empty())
+        if (gpr32_64_alias)
             return true;
         for (auto &sa : li.segments)
             for (auto &sb : other->segments)
@@ -501,7 +501,7 @@ LiveInterval *LiveRegMatrix::GetConflict(const LiveInterval &li,
         bool gpr32_64_alias =
             (li.reg_class == RegClass::GPR32 && other->reg_class == RegClass::GPR64) ||
             (li.reg_class == RegClass::GPR64 && other->reg_class == RegClass::GPR32);
-        if (gpr32_64_alias && !li.segments.empty() && !other->segments.empty())
+        if (gpr32_64_alias)
             return other;
         for (auto &sa : li.segments)
             for (auto &sb : other->segments)