fix(goobj): make R_DWTXTADDR_U4 relocation type Go-version-aware

The relocation type number shifted between Go 1.26 (103) and Go 1.27
(106)
because new LoongArch relocations were inserted. Detect the Go version
at
runtime and use the correct value.

asm/goobj_test.go

@@ -186,7 +186,7 @@ DATA mask<>+8(SB)/8, $0x800f0e0d0c0b0a09
 		t.Errorf("addq lines reloc = %x", lr)
 	}
 	dr := relocs[23:46]
-	if dr[4] != 4 || le.Uint16(dr[5:]) != relocDWTXTADDRU4 ||
+	if dr[4] != 4 || le.Uint16(dr[5:]) != relocDWTXTADDRU4() ||
 		le.Uint32(dr[15:]) != pkgIdxNone || le.Uint32(dr[19:]) != 4 {
 		t.Errorf("addq DIE reloc = %x", dr)
 	}